Mercurial > hg > truffle
annotate src/share/vm/opto/loopnode.cpp @ 4112:e8fdaf4a66cb
7110586: C2 generates incorrect results
Summary: Exact limit of empty loop calculated incorrectly.
Reviewed-by: iveresov, never
| author | kvn |
|---|---|
| date | Thu, 10 Nov 2011 20:17:05 -0800 |
| parents | 670a74b863fc |
| children | 1bd45abaa507 |
| rev | line source |
|---|---|
| 0 | 1 /* |
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2 * Copyright (c) 1998, 2011, Oracle and/or its affiliates. All rights reserved. |
| 0 | 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 * | |
| 5 * This code is free software; you can redistribute it and/or modify it | |
| 6 * under the terms of the GNU General Public License version 2 only, as | |
| 7 * published by the Free Software Foundation. | |
| 8 * | |
| 9 * This code is distributed in the hope that it will be useful, but WITHOUT | |
| 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 12 * version 2 for more details (a copy is included in the LICENSE file that | |
| 13 * accompanied this code). | |
| 14 * | |
| 15 * You should have received a copy of the GNU General Public License version | |
| 16 * 2 along with this work; if not, write to the Free Software Foundation, | |
| 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
| 18 * | |
|
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
| 0 | 22 * |
| 23 */ | |
| 24 | |
| 1972 | 25 #include "precompiled.hpp" |
| 26 #include "ci/ciMethodData.hpp" | |
| 27 #include "compiler/compileLog.hpp" | |
| 28 #include "libadt/vectset.hpp" | |
| 29 #include "memory/allocation.inline.hpp" | |
| 30 #include "opto/addnode.hpp" | |
| 31 #include "opto/callnode.hpp" | |
| 32 #include "opto/connode.hpp" | |
| 33 #include "opto/divnode.hpp" | |
| 34 #include "opto/idealGraphPrinter.hpp" | |
| 35 #include "opto/loopnode.hpp" | |
| 36 #include "opto/mulnode.hpp" | |
| 37 #include "opto/rootnode.hpp" | |
| 38 #include "opto/superword.hpp" | |
| 0 | 39 |
| 40 //============================================================================= | |
| 41 //------------------------------is_loop_iv------------------------------------- | |
| 42 // Determine if a node is Counted loop induction variable. | |
| 43 // The method is declared in node.hpp. | |
| 44 const Node* Node::is_loop_iv() const { | |
| 45 if (this->is_Phi() && !this->as_Phi()->is_copy() && | |
| 46 this->as_Phi()->region()->is_CountedLoop() && | |
| 47 this->as_Phi()->region()->as_CountedLoop()->phi() == this) { | |
| 48 return this; | |
| 49 } else { | |
| 50 return NULL; | |
| 51 } | |
| 52 } | |
| 53 | |
| 54 //============================================================================= | |
| 55 //------------------------------dump_spec-------------------------------------- | |
| 56 // Dump special per-node info | |
| 57 #ifndef PRODUCT | |
| 58 void LoopNode::dump_spec(outputStream *st) const { | |
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59 if (is_inner_loop()) st->print( "inner " ); |
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60 if (is_partial_peel_loop()) st->print( "partial_peel " ); |
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61 if (partial_peel_has_failed()) st->print( "partial_peel_failed " ); |
| 0 | 62 } |
| 63 #endif | |
| 64 | |
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65 //------------------------------is_valid_counted_loop------------------------- |
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66 bool LoopNode::is_valid_counted_loop() const { |
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67 if (is_CountedLoop()) { |
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68 CountedLoopNode* l = as_CountedLoop(); |
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69 CountedLoopEndNode* le = l->loopexit(); |
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70 if (le != NULL && |
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71 le->proj_out(1 /* true */) == l->in(LoopNode::LoopBackControl)) { |
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72 Node* phi = l->phi(); |
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73 Node* exit = le->proj_out(0 /* false */); |
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74 if (exit != NULL && exit->Opcode() == Op_IfFalse && |
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75 phi != NULL && phi->is_Phi() && |
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76 phi->in(LoopNode::LoopBackControl) == l->incr() && |
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77 le->loopnode() == l && le->stride_is_con()) { |
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78 return true; |
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79 } |
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80 } |
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81 } |
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82 return false; |
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83 } |
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84 |
| 0 | 85 //------------------------------get_early_ctrl--------------------------------- |
| 86 // Compute earliest legal control | |
| 87 Node *PhaseIdealLoop::get_early_ctrl( Node *n ) { | |
| 88 assert( !n->is_Phi() && !n->is_CFG(), "this code only handles data nodes" ); | |
| 89 uint i; | |
| 90 Node *early; | |
| 91 if( n->in(0) ) { | |
| 92 early = n->in(0); | |
| 93 if( !early->is_CFG() ) // Might be a non-CFG multi-def | |
| 94 early = get_ctrl(early); // So treat input as a straight data input | |
| 95 i = 1; | |
| 96 } else { | |
| 97 early = get_ctrl(n->in(1)); | |
| 98 i = 2; | |
| 99 } | |
| 100 uint e_d = dom_depth(early); | |
| 101 assert( early, "" ); | |
| 102 for( ; i < n->req(); i++ ) { | |
| 103 Node *cin = get_ctrl(n->in(i)); | |
| 104 assert( cin, "" ); | |
| 105 // Keep deepest dominator depth | |
| 106 uint c_d = dom_depth(cin); | |
| 107 if( c_d > e_d ) { // Deeper guy? | |
| 108 early = cin; // Keep deepest found so far | |
| 109 e_d = c_d; | |
| 110 } else if( c_d == e_d && // Same depth? | |
| 111 early != cin ) { // If not equal, must use slower algorithm | |
| 112 // If same depth but not equal, one _must_ dominate the other | |
| 113 // and we want the deeper (i.e., dominated) guy. | |
| 114 Node *n1 = early; | |
| 115 Node *n2 = cin; | |
| 116 while( 1 ) { | |
| 117 n1 = idom(n1); // Walk up until break cycle | |
| 118 n2 = idom(n2); | |
| 119 if( n1 == cin || // Walked early up to cin | |
| 120 dom_depth(n2) < c_d ) | |
| 121 break; // early is deeper; keep him | |
| 122 if( n2 == early || // Walked cin up to early | |
| 123 dom_depth(n1) < c_d ) { | |
| 124 early = cin; // cin is deeper; keep him | |
| 125 break; | |
| 126 } | |
| 127 } | |
| 128 e_d = dom_depth(early); // Reset depth register cache | |
| 129 } | |
| 130 } | |
| 131 | |
| 132 // Return earliest legal location | |
| 133 assert(early == find_non_split_ctrl(early), "unexpected early control"); | |
| 134 | |
| 135 return early; | |
| 136 } | |
| 137 | |
| 138 //------------------------------set_early_ctrl--------------------------------- | |
| 139 // Set earliest legal control | |
| 140 void PhaseIdealLoop::set_early_ctrl( Node *n ) { | |
| 141 Node *early = get_early_ctrl(n); | |
| 142 | |
| 143 // Record earliest legal location | |
| 144 set_ctrl(n, early); | |
| 145 } | |
| 146 | |
| 147 //------------------------------set_subtree_ctrl------------------------------- | |
| 148 // set missing _ctrl entries on new nodes | |
| 149 void PhaseIdealLoop::set_subtree_ctrl( Node *n ) { | |
| 150 // Already set? Get out. | |
| 151 if( _nodes[n->_idx] ) return; | |
| 152 // Recursively set _nodes array to indicate where the Node goes | |
| 153 uint i; | |
| 154 for( i = 0; i < n->req(); ++i ) { | |
| 155 Node *m = n->in(i); | |
| 156 if( m && m != C->root() ) | |
| 157 set_subtree_ctrl( m ); | |
| 158 } | |
| 159 | |
| 160 // Fixup self | |
| 161 set_early_ctrl( n ); | |
| 162 } | |
| 163 | |
| 164 //------------------------------is_counted_loop-------------------------------- | |
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165 bool PhaseIdealLoop::is_counted_loop( Node *x, IdealLoopTree *loop ) { |
| 0 | 166 PhaseGVN *gvn = &_igvn; |
| 167 | |
| 168 // Counted loop head must be a good RegionNode with only 3 not NULL | |
| 169 // control input edges: Self, Entry, LoopBack. | |
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170 if (x->in(LoopNode::Self) == NULL || x->req() != 3) |
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171 return false; |
| 0 | 172 |
| 173 Node *init_control = x->in(LoopNode::EntryControl); | |
| 174 Node *back_control = x->in(LoopNode::LoopBackControl); | |
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175 if (init_control == NULL || back_control == NULL) // Partially dead |
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176 return false; |
| 0 | 177 // Must also check for TOP when looking for a dead loop |
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178 if (init_control->is_top() || back_control->is_top()) |
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179 return false; |
| 0 | 180 |
| 181 // Allow funny placement of Safepoint | |
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182 if (back_control->Opcode() == Op_SafePoint) |
| 0 | 183 back_control = back_control->in(TypeFunc::Control); |
| 184 | |
| 185 // Controlling test for loop | |
| 186 Node *iftrue = back_control; | |
| 187 uint iftrue_op = iftrue->Opcode(); | |
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188 if (iftrue_op != Op_IfTrue && |
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189 iftrue_op != Op_IfFalse) |
| 0 | 190 // I have a weird back-control. Probably the loop-exit test is in |
| 191 // the middle of the loop and I am looking at some trailing control-flow | |
| 192 // merge point. To fix this I would have to partially peel the loop. | |
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193 return false; // Obscure back-control |
| 0 | 194 |
| 195 // Get boolean guarding loop-back test | |
| 196 Node *iff = iftrue->in(0); | |
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197 if (get_loop(iff) != loop || !iff->in(1)->is_Bool()) |
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198 return false; |
| 0 | 199 BoolNode *test = iff->in(1)->as_Bool(); |
| 200 BoolTest::mask bt = test->_test._test; | |
| 201 float cl_prob = iff->as_If()->_prob; | |
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202 if (iftrue_op == Op_IfFalse) { |
| 0 | 203 bt = BoolTest(bt).negate(); |
| 204 cl_prob = 1.0 - cl_prob; | |
| 205 } | |
| 206 // Get backedge compare | |
| 207 Node *cmp = test->in(1); | |
| 208 int cmp_op = cmp->Opcode(); | |
| 3345 | 209 if (cmp_op != Op_CmpI) |
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210 return false; // Avoid pointer & float compares |
| 0 | 211 |
| 212 // Find the trip-counter increment & limit. Limit must be loop invariant. | |
| 213 Node *incr = cmp->in(1); | |
| 214 Node *limit = cmp->in(2); | |
| 215 | |
| 216 // --------- | |
| 217 // need 'loop()' test to tell if limit is loop invariant | |
| 218 // --------- | |
| 219 | |
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220 if (!is_member(loop, get_ctrl(incr))) { // Swapped trip counter and limit? |
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221 Node *tmp = incr; // Then reverse order into the CmpI |
| 0 | 222 incr = limit; |
| 223 limit = tmp; | |
| 224 bt = BoolTest(bt).commute(); // And commute the exit test | |
| 225 } | |
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226 if (is_member(loop, get_ctrl(limit))) // Limit must be loop-invariant |
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227 return false; |
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228 if (!is_member(loop, get_ctrl(incr))) // Trip counter must be loop-variant |
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229 return false; |
| 0 | 230 |
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231 Node* phi_incr = NULL; |
| 0 | 232 // Trip-counter increment must be commutative & associative. |
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233 if (incr->is_Phi()) { |
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234 if (incr->as_Phi()->region() != x || incr->req() != 3) |
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235 return false; // Not simple trip counter expression |
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236 phi_incr = incr; |
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237 incr = phi_incr->in(LoopNode::LoopBackControl); // Assume incr is on backedge of Phi |
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238 if (!is_member(loop, get_ctrl(incr))) // Trip counter must be loop-variant |
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239 return false; |
| 0 | 240 } |
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241 |
| 0 | 242 Node* trunc1 = NULL; |
| 243 Node* trunc2 = NULL; | |
| 244 const TypeInt* iv_trunc_t = NULL; | |
| 245 if (!(incr = CountedLoopNode::match_incr_with_optional_truncation(incr, &trunc1, &trunc2, &iv_trunc_t))) { | |
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246 return false; // Funny increment opcode |
| 0 | 247 } |
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248 assert(incr->Opcode() == Op_AddI, "wrong increment code"); |
| 0 | 249 |
| 250 // Get merge point | |
| 251 Node *xphi = incr->in(1); | |
| 252 Node *stride = incr->in(2); | |
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253 if (!stride->is_Con()) { // Oops, swap these |
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254 if (!xphi->is_Con()) // Is the other guy a constant? |
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255 return false; // Nope, unknown stride, bail out |
| 0 | 256 Node *tmp = xphi; // 'incr' is commutative, so ok to swap |
| 257 xphi = stride; | |
| 258 stride = tmp; | |
| 259 } | |
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260 // Stride must be constant |
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261 int stride_con = stride->get_int(); |
| 3345 | 262 if (stride_con == 0) |
| 263 return false; // missed some peephole opt | |
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264 |
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265 if (!xphi->is_Phi()) |
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266 return false; // Too much math on the trip counter |
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267 if (phi_incr != NULL && phi_incr != xphi) |
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268 return false; |
| 0 | 269 PhiNode *phi = xphi->as_Phi(); |
| 270 | |
| 271 // Phi must be of loop header; backedge must wrap to increment | |
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272 if (phi->region() != x) |
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273 return false; |
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274 if (trunc1 == NULL && phi->in(LoopNode::LoopBackControl) != incr || |
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275 trunc1 != NULL && phi->in(LoopNode::LoopBackControl) != trunc1) { |
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276 return false; |
| 0 | 277 } |
| 278 Node *init_trip = phi->in(LoopNode::EntryControl); | |
| 279 | |
| 280 // If iv trunc type is smaller than int, check for possible wrap. | |
| 281 if (!TypeInt::INT->higher_equal(iv_trunc_t)) { | |
| 282 assert(trunc1 != NULL, "must have found some truncation"); | |
| 283 | |
| 284 // Get a better type for the phi (filtered thru if's) | |
| 285 const TypeInt* phi_ft = filtered_type(phi); | |
| 286 | |
| 287 // Can iv take on a value that will wrap? | |
| 288 // | |
| 289 // Ensure iv's limit is not within "stride" of the wrap value. | |
| 290 // | |
| 291 // Example for "short" type | |
| 292 // Truncation ensures value is in the range -32768..32767 (iv_trunc_t) | |
| 293 // If the stride is +10, then the last value of the induction | |
| 294 // variable before the increment (phi_ft->_hi) must be | |
| 295 // <= 32767 - 10 and (phi_ft->_lo) must be >= -32768 to | |
| 296 // ensure no truncation occurs after the increment. | |
| 297 | |
| 298 if (stride_con > 0) { | |
| 299 if (iv_trunc_t->_hi - phi_ft->_hi < stride_con || | |
| 300 iv_trunc_t->_lo > phi_ft->_lo) { | |
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301 return false; // truncation may occur |
| 0 | 302 } |
| 303 } else if (stride_con < 0) { | |
| 304 if (iv_trunc_t->_lo - phi_ft->_lo > stride_con || | |
| 305 iv_trunc_t->_hi < phi_ft->_hi) { | |
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306 return false; // truncation may occur |
| 0 | 307 } |
| 308 } | |
| 309 // No possibility of wrap so truncation can be discarded | |
| 310 // Promote iv type to Int | |
| 311 } else { | |
| 312 assert(trunc1 == NULL && trunc2 == NULL, "no truncation for int"); | |
| 313 } | |
| 314 | |
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315 // If the condition is inverted and we will be rolling |
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316 // through MININT to MAXINT, then bail out. |
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317 if (bt == BoolTest::eq || // Bail out, but this loop trips at most twice! |
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318 // Odd stride |
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319 bt == BoolTest::ne && stride_con != 1 && stride_con != -1 || |
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320 // Count down loop rolls through MAXINT |
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321 (bt == BoolTest::le || bt == BoolTest::lt) && stride_con < 0 || |
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322 // Count up loop rolls through MININT |
| 3345 | 323 (bt == BoolTest::ge || bt == BoolTest::gt) && stride_con > 0) { |
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324 return false; // Bail out |
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325 } |
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326 |
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327 const TypeInt* init_t = gvn->type(init_trip)->is_int(); |
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328 const TypeInt* limit_t = gvn->type(limit)->is_int(); |
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329 |
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330 if (stride_con > 0) { |
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331 long init_p = (long)init_t->_lo + stride_con; |
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332 if (init_p > (long)max_jint || init_p > (long)limit_t->_hi) |
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333 return false; // cyclic loop or this loop trips only once |
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334 } else { |
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335 long init_p = (long)init_t->_hi + stride_con; |
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336 if (init_p < (long)min_jint || init_p < (long)limit_t->_lo) |
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337 return false; // cyclic loop or this loop trips only once |
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338 } |
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339 |
| 0 | 340 // ================================================= |
| 341 // ---- SUCCESS! Found A Trip-Counted Loop! ----- | |
| 342 // | |
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343 assert(x->Opcode() == Op_Loop, "regular loops only"); |
| 0 | 344 C->print_method("Before CountedLoop", 3); |
| 3345 | 345 |
| 346 Node *hook = new (C, 6) Node(6); | |
| 347 | |
| 348 if (LoopLimitCheck) { | |
| 349 | |
| 350 // =================================================== | |
| 351 // Generate loop limit check to avoid integer overflow | |
| 352 // in cases like next (cyclic loops): | |
| 353 // | |
| 354 // for (i=0; i <= max_jint; i++) {} | |
| 355 // for (i=0; i < max_jint; i+=2) {} | |
| 356 // | |
| 357 // | |
| 358 // Limit check predicate depends on the loop test: | |
| 359 // | |
| 360 // for(;i != limit; i++) --> limit <= (max_jint) | |
| 361 // for(;i < limit; i+=stride) --> limit <= (max_jint - stride + 1) | |
| 362 // for(;i <= limit; i+=stride) --> limit <= (max_jint - stride ) | |
| 363 // | |
| 364 | |
| 365 // Check if limit is excluded to do more precise int overflow check. | |
| 366 bool incl_limit = (bt == BoolTest::le || bt == BoolTest::ge); | |
| 367 int stride_m = stride_con - (incl_limit ? 0 : (stride_con > 0 ? 1 : -1)); | |
| 368 | |
| 369 // If compare points directly to the phi we need to adjust | |
| 370 // the compare so that it points to the incr. Limit have | |
| 371 // to be adjusted to keep trip count the same and the | |
| 372 // adjusted limit should be checked for int overflow. | |
| 373 if (phi_incr != NULL) { | |
| 374 stride_m += stride_con; | |
| 375 } | |
| 376 | |
| 377 if (limit->is_Con()) { | |
| 378 int limit_con = limit->get_int(); | |
| 379 if ((stride_con > 0 && limit_con > (max_jint - stride_m)) || | |
| 380 (stride_con < 0 && limit_con < (min_jint - stride_m))) { | |
| 381 // Bailout: it could be integer overflow. | |
| 382 return false; | |
| 383 } | |
| 384 } else if ((stride_con > 0 && limit_t->_hi <= (max_jint - stride_m)) || | |
| 385 (stride_con < 0 && limit_t->_lo >= (min_jint - stride_m))) { | |
| 386 // Limit's type may satisfy the condition, for example, | |
| 387 // when it is an array length. | |
| 388 } else { | |
| 389 // Generate loop's limit check. | |
| 390 // Loop limit check predicate should be near the loop. | |
| 391 ProjNode *limit_check_proj = find_predicate_insertion_point(init_control, Deoptimization::Reason_loop_limit_check); | |
| 392 if (!limit_check_proj) { | |
| 393 // The limit check predicate is not generated if this method trapped here before. | |
| 394 #ifdef ASSERT | |
| 395 if (TraceLoopLimitCheck) { | |
| 396 tty->print("missing loop limit check:"); | |
| 397 loop->dump_head(); | |
| 398 x->dump(1); | |
| 399 } | |
| 400 #endif | |
| 401 return false; | |
| 402 } | |
| 403 | |
| 404 IfNode* check_iff = limit_check_proj->in(0)->as_If(); | |
| 405 Node* cmp_limit; | |
| 406 Node* bol; | |
| 407 | |
| 408 if (stride_con > 0) { | |
| 409 cmp_limit = new (C, 3) CmpINode(limit, _igvn.intcon(max_jint - stride_m)); | |
| 410 bol = new (C, 2) BoolNode(cmp_limit, BoolTest::le); | |
| 411 } else { | |
| 412 cmp_limit = new (C, 3) CmpINode(limit, _igvn.intcon(min_jint - stride_m)); | |
| 413 bol = new (C, 2) BoolNode(cmp_limit, BoolTest::ge); | |
| 414 } | |
| 415 cmp_limit = _igvn.register_new_node_with_optimizer(cmp_limit); | |
| 416 bol = _igvn.register_new_node_with_optimizer(bol); | |
| 417 set_subtree_ctrl(bol); | |
| 418 | |
| 419 // Replace condition in original predicate but preserve Opaque node | |
| 420 // so that previous predicates could be found. | |
| 421 assert(check_iff->in(1)->Opcode() == Op_Conv2B && | |
| 422 check_iff->in(1)->in(1)->Opcode() == Op_Opaque1, ""); | |
| 423 Node* opq = check_iff->in(1)->in(1); | |
| 424 _igvn.hash_delete(opq); | |
| 425 opq->set_req(1, bol); | |
| 426 // Update ctrl. | |
| 427 set_ctrl(opq, check_iff->in(0)); | |
| 428 set_ctrl(check_iff->in(1), check_iff->in(0)); | |
| 429 | |
| 2445 | 430 #ifndef PRODUCT |
| 3345 | 431 // report that the loop predication has been actually performed |
| 432 // for this loop | |
| 433 if (TraceLoopLimitCheck) { | |
| 434 tty->print_cr("Counted Loop Limit Check generated:"); | |
| 435 debug_only( bol->dump(2); ) | |
| 436 } | |
| 437 #endif | |
| 438 } | |
| 439 | |
| 440 if (phi_incr != NULL) { | |
| 441 // If compare points directly to the phi we need to adjust | |
| 442 // the compare so that it points to the incr. Limit have | |
| 443 // to be adjusted to keep trip count the same and we | |
| 444 // should avoid int overflow. | |
| 445 // | |
| 446 // i = init; do {} while(i++ < limit); | |
| 447 // is converted to | |
| 448 // i = init; do {} while(++i < limit+1); | |
| 449 // | |
| 450 limit = gvn->transform(new (C, 3) AddINode(limit, stride)); | |
| 2445 | 451 } |
| 3345 | 452 |
| 453 // Now we need to canonicalize loop condition. | |
| 454 if (bt == BoolTest::ne) { | |
| 455 assert(stride_con == 1 || stride_con == -1, "simple increment only"); | |
| 3782 | 456 // 'ne' can be replaced with 'lt' only when init < limit. |
| 457 if (stride_con > 0 && init_t->_hi < limit_t->_lo) | |
| 458 bt = BoolTest::lt; | |
| 459 // 'ne' can be replaced with 'gt' only when init > limit. | |
| 460 if (stride_con < 0 && init_t->_lo > limit_t->_hi) | |
| 461 bt = BoolTest::gt; | |
| 3345 | 462 } |
| 463 | |
| 464 if (incl_limit) { | |
| 465 // The limit check guaranties that 'limit <= (max_jint - stride)' so | |
| 466 // we can convert 'i <= limit' to 'i < limit+1' since stride != 0. | |
| 467 // | |
| 468 Node* one = (stride_con > 0) ? gvn->intcon( 1) : gvn->intcon(-1); | |
| 469 limit = gvn->transform(new (C, 3) AddINode(limit, one)); | |
| 470 if (bt == BoolTest::le) | |
| 471 bt = BoolTest::lt; | |
| 472 else if (bt == BoolTest::ge) | |
| 473 bt = BoolTest::gt; | |
| 474 else | |
| 475 ShouldNotReachHere(); | |
| 476 } | |
| 477 set_subtree_ctrl( limit ); | |
| 478 | |
| 479 } else { // LoopLimitCheck | |
| 480 | |
| 0 | 481 // If compare points to incr, we are ok. Otherwise the compare |
| 482 // can directly point to the phi; in this case adjust the compare so that | |
| 605 | 483 // it points to the incr by adjusting the limit. |
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484 if (cmp->in(1) == phi || cmp->in(2) == phi) |
| 0 | 485 limit = gvn->transform(new (C, 3) AddINode(limit,stride)); |
| 486 | |
| 487 // trip-count for +-tive stride should be: (limit - init_trip + stride - 1)/stride. | |
| 488 // Final value for iterator should be: trip_count * stride + init_trip. | |
| 489 Node *one_p = gvn->intcon( 1); | |
| 490 Node *one_m = gvn->intcon(-1); | |
| 491 | |
| 492 Node *trip_count = NULL; | |
| 493 switch( bt ) { | |
| 494 case BoolTest::eq: | |
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495 ShouldNotReachHere(); |
| 0 | 496 case BoolTest::ne: // Ahh, the case we desire |
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497 if (stride_con == 1) |
| 0 | 498 trip_count = gvn->transform(new (C, 3) SubINode(limit,init_trip)); |
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499 else if (stride_con == -1) |
| 0 | 500 trip_count = gvn->transform(new (C, 3) SubINode(init_trip,limit)); |
| 501 else | |
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502 ShouldNotReachHere(); |
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503 set_subtree_ctrl(trip_count); |
| 0 | 504 //_loop.map(trip_count->_idx,loop(limit)); |
| 505 break; | |
| 506 case BoolTest::le: // Maybe convert to '<' case | |
| 507 limit = gvn->transform(new (C, 3) AddINode(limit,one_p)); | |
| 508 set_subtree_ctrl( limit ); | |
| 509 hook->init_req(4, limit); | |
| 510 | |
| 511 bt = BoolTest::lt; | |
| 512 // Make the new limit be in the same loop nest as the old limit | |
| 513 //_loop.map(limit->_idx,limit_loop); | |
| 514 // Fall into next case | |
| 515 case BoolTest::lt: { // Maybe convert to '!=' case | |
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516 if (stride_con < 0) // Count down loop rolls through MAXINT |
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517 ShouldNotReachHere(); |
| 0 | 518 Node *range = gvn->transform(new (C, 3) SubINode(limit,init_trip)); |
| 519 set_subtree_ctrl( range ); | |
| 520 hook->init_req(0, range); | |
| 521 | |
| 522 Node *bias = gvn->transform(new (C, 3) AddINode(range,stride)); | |
| 523 set_subtree_ctrl( bias ); | |
| 524 hook->init_req(1, bias); | |
| 525 | |
| 526 Node *bias1 = gvn->transform(new (C, 3) AddINode(bias,one_m)); | |
| 527 set_subtree_ctrl( bias1 ); | |
| 528 hook->init_req(2, bias1); | |
| 529 | |
| 530 trip_count = gvn->transform(new (C, 3) DivINode(0,bias1,stride)); | |
| 531 set_subtree_ctrl( trip_count ); | |
| 532 hook->init_req(3, trip_count); | |
| 533 break; | |
| 534 } | |
| 535 | |
| 536 case BoolTest::ge: // Maybe convert to '>' case | |
| 537 limit = gvn->transform(new (C, 3) AddINode(limit,one_m)); | |
| 538 set_subtree_ctrl( limit ); | |
| 539 hook->init_req(4 ,limit); | |
| 540 | |
| 541 bt = BoolTest::gt; | |
| 542 // Make the new limit be in the same loop nest as the old limit | |
| 543 //_loop.map(limit->_idx,limit_loop); | |
| 544 // Fall into next case | |
| 545 case BoolTest::gt: { // Maybe convert to '!=' case | |
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546 if (stride_con > 0) // count up loop rolls through MININT |
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547 ShouldNotReachHere(); |
| 0 | 548 Node *range = gvn->transform(new (C, 3) SubINode(limit,init_trip)); |
| 549 set_subtree_ctrl( range ); | |
| 550 hook->init_req(0, range); | |
| 551 | |
| 552 Node *bias = gvn->transform(new (C, 3) AddINode(range,stride)); | |
| 553 set_subtree_ctrl( bias ); | |
| 554 hook->init_req(1, bias); | |
| 555 | |
| 556 Node *bias1 = gvn->transform(new (C, 3) AddINode(bias,one_p)); | |
| 557 set_subtree_ctrl( bias1 ); | |
| 558 hook->init_req(2, bias1); | |
| 559 | |
| 560 trip_count = gvn->transform(new (C, 3) DivINode(0,bias1,stride)); | |
| 561 set_subtree_ctrl( trip_count ); | |
| 562 hook->init_req(3, trip_count); | |
| 563 break; | |
| 564 } | |
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565 } // switch( bt ) |
| 0 | 566 |
| 567 Node *span = gvn->transform(new (C, 3) MulINode(trip_count,stride)); | |
| 568 set_subtree_ctrl( span ); | |
| 569 hook->init_req(5, span); | |
| 570 | |
| 571 limit = gvn->transform(new (C, 3) AddINode(span,init_trip)); | |
| 572 set_subtree_ctrl( limit ); | |
| 573 | |
| 3345 | 574 } // LoopLimitCheck |
| 575 | |
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576 // Check for SafePoint on backedge and remove |
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577 Node *sfpt = x->in(LoopNode::LoopBackControl); |
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578 if (sfpt->Opcode() == Op_SafePoint && is_deleteable_safept(sfpt)) { |
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579 lazy_replace( sfpt, iftrue ); |
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580 loop->_tail = iftrue; |
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581 } |
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582 |
| 0 | 583 // Build a canonical trip test. |
| 584 // Clone code, as old values may be in use. | |
| 585 incr = incr->clone(); | |
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586 incr->set_req(1,phi); |
| 0 | 587 incr->set_req(2,stride); |
| 588 incr = _igvn.register_new_node_with_optimizer(incr); | |
| 589 set_early_ctrl( incr ); | |
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590 _igvn.hash_delete(phi); |
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591 phi->set_req_X( LoopNode::LoopBackControl, incr, &_igvn ); |
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592 |
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593 // If phi type is more restrictive than Int, raise to |
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594 // Int to prevent (almost) infinite recursion in igvn |
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595 // which can only handle integer types for constants or minint..maxint. |
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596 if (!TypeInt::INT->higher_equal(phi->bottom_type())) { |
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597 Node* nphi = PhiNode::make(phi->in(0), phi->in(LoopNode::EntryControl), TypeInt::INT); |
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598 nphi->set_req(LoopNode::LoopBackControl, phi->in(LoopNode::LoopBackControl)); |
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599 nphi = _igvn.register_new_node_with_optimizer(nphi); |
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600 set_ctrl(nphi, get_ctrl(phi)); |
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601 _igvn.replace_node(phi, nphi); |
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602 phi = nphi->as_Phi(); |
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603 } |
| 0 | 604 cmp = cmp->clone(); |
| 605 cmp->set_req(1,incr); | |
| 606 cmp->set_req(2,limit); | |
| 607 cmp = _igvn.register_new_node_with_optimizer(cmp); | |
| 608 set_ctrl(cmp, iff->in(0)); | |
| 609 | |
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610 test = test->clone()->as_Bool(); |
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611 (*(BoolTest*)&test->_test)._test = bt; |
| 0 | 612 test->set_req(1,cmp); |
| 613 _igvn.register_new_node_with_optimizer(test); | |
| 614 set_ctrl(test, iff->in(0)); | |
| 615 | |
| 616 // Replace the old IfNode with a new LoopEndNode | |
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617 Node *lex = _igvn.register_new_node_with_optimizer(new (C, 2) CountedLoopEndNode( iff->in(0), test, cl_prob, iff->as_If()->_fcnt )); |
| 0 | 618 IfNode *le = lex->as_If(); |
| 619 uint dd = dom_depth(iff); | |
| 620 set_idom(le, le->in(0), dd); // Update dominance for loop exit | |
| 621 set_loop(le, loop); | |
| 622 | |
| 623 // Get the loop-exit control | |
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624 Node *iffalse = iff->as_If()->proj_out(!(iftrue_op == Op_IfTrue)); |
| 0 | 625 |
| 626 // Need to swap loop-exit and loop-back control? | |
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627 if (iftrue_op == Op_IfFalse) { |
| 0 | 628 Node *ift2=_igvn.register_new_node_with_optimizer(new (C, 1) IfTrueNode (le)); |
| 629 Node *iff2=_igvn.register_new_node_with_optimizer(new (C, 1) IfFalseNode(le)); | |
| 630 | |
| 631 loop->_tail = back_control = ift2; | |
| 632 set_loop(ift2, loop); | |
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633 set_loop(iff2, get_loop(iffalse)); |
| 0 | 634 |
| 635 // Lazy update of 'get_ctrl' mechanism. | |
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636 lazy_replace_proj( iffalse, iff2 ); |
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637 lazy_replace_proj( iftrue, ift2 ); |
| 0 | 638 |
| 639 // Swap names | |
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640 iffalse = iff2; |
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641 iftrue = ift2; |
| 0 | 642 } else { |
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643 _igvn.hash_delete(iffalse); |
| 0 | 644 _igvn.hash_delete(iftrue); |
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645 iffalse->set_req_X( 0, le, &_igvn ); |
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646 iftrue ->set_req_X( 0, le, &_igvn ); |
| 0 | 647 } |
| 648 | |
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649 set_idom(iftrue, le, dd+1); |
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650 set_idom(iffalse, le, dd+1); |
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651 assert(iff->outcnt() == 0, "should be dead now"); |
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652 lazy_replace( iff, le ); // fix 'get_ctrl' |
| 0 | 653 |
| 654 // Now setup a new CountedLoopNode to replace the existing LoopNode | |
| 655 CountedLoopNode *l = new (C, 3) CountedLoopNode(init_control, back_control); | |
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656 l->set_unswitch_count(x->as_Loop()->unswitch_count()); // Preserve |
| 0 | 657 // The following assert is approximately true, and defines the intention |
| 658 // of can_be_counted_loop. It fails, however, because phase->type | |
| 659 // is not yet initialized for this loop and its parts. | |
| 660 //assert(l->can_be_counted_loop(this), "sanity"); | |
| 661 _igvn.register_new_node_with_optimizer(l); | |
| 662 set_loop(l, loop); | |
| 663 loop->_head = l; | |
| 664 // Fix all data nodes placed at the old loop head. | |
| 665 // Uses the lazy-update mechanism of 'get_ctrl'. | |
| 666 lazy_replace( x, l ); | |
| 667 set_idom(l, init_control, dom_depth(x)); | |
| 668 | |
| 605 | 669 // Check for immediately preceding SafePoint and remove |
| 0 | 670 Node *sfpt2 = le->in(0); |
| 3345 | 671 if (sfpt2->Opcode() == Op_SafePoint && is_deleteable_safept(sfpt2)) |
| 0 | 672 lazy_replace( sfpt2, sfpt2->in(TypeFunc::Control)); |
| 673 | |
| 674 // Free up intermediate goo | |
| 675 _igvn.remove_dead_node(hook); | |
| 676 | |
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677 #ifdef ASSERT |
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678 assert(l->is_valid_counted_loop(), "counted loop shape is messed up"); |
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679 assert(l == loop->_head && l->phi() == phi && l->loopexit() == lex, "" ); |
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680 #endif |
| 3345 | 681 #ifndef PRODUCT |
| 682 if (TraceLoopOpts) { | |
| 683 tty->print("Counted "); | |
| 684 loop->dump_head(); | |
| 685 } | |
| 686 #endif | |
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687 |
| 0 | 688 C->print_method("After CountedLoop", 3); |
| 689 | |
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690 return true; |
| 0 | 691 } |
| 692 | |
| 3345 | 693 //----------------------exact_limit------------------------------------------- |
| 694 Node* PhaseIdealLoop::exact_limit( IdealLoopTree *loop ) { | |
| 695 assert(loop->_head->is_CountedLoop(), ""); | |
| 696 CountedLoopNode *cl = loop->_head->as_CountedLoop(); | |
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697 assert(cl->is_valid_counted_loop(), ""); |
| 3345 | 698 |
| 699 if (!LoopLimitCheck || ABS(cl->stride_con()) == 1 || | |
| 700 cl->limit()->Opcode() == Op_LoopLimit) { | |
| 701 // Old code has exact limit (it could be incorrect in case of int overflow). | |
| 702 // Loop limit is exact with stride == 1. And loop may already have exact limit. | |
| 703 return cl->limit(); | |
| 704 } | |
| 705 Node *limit = NULL; | |
| 706 #ifdef ASSERT | |
| 707 BoolTest::mask bt = cl->loopexit()->test_trip(); | |
| 708 assert(bt == BoolTest::lt || bt == BoolTest::gt, "canonical test is expected"); | |
| 709 #endif | |
| 710 if (cl->has_exact_trip_count()) { | |
| 711 // Simple case: loop has constant boundaries. | |
| 712 // Use longs to avoid integer overflow. | |
| 713 int stride_con = cl->stride_con(); | |
| 714 long init_con = cl->init_trip()->get_int(); | |
| 715 long limit_con = cl->limit()->get_int(); | |
| 716 julong trip_cnt = cl->trip_count(); | |
| 717 long final_con = init_con + trip_cnt*stride_con; | |
| 718 int final_int = (int)final_con; | |
| 719 // The final value should be in integer range since the loop | |
| 720 // is counted and the limit was checked for overflow. | |
| 721 assert(final_con == (long)final_int, "final value should be integer"); | |
| 722 limit = _igvn.intcon(final_int); | |
| 723 } else { | |
| 724 // Create new LoopLimit node to get exact limit (final iv value). | |
| 725 limit = new (C, 4) LoopLimitNode(C, cl->init_trip(), cl->limit(), cl->stride()); | |
| 726 register_new_node(limit, cl->in(LoopNode::EntryControl)); | |
| 727 } | |
| 728 assert(limit != NULL, "sanity"); | |
| 729 return limit; | |
| 730 } | |
| 0 | 731 |
| 732 //------------------------------Ideal------------------------------------------ | |
| 733 // Return a node which is more "ideal" than the current node. | |
| 734 // Attempt to convert into a counted-loop. | |
| 735 Node *LoopNode::Ideal(PhaseGVN *phase, bool can_reshape) { | |
| 736 if (!can_be_counted_loop(phase)) { | |
| 737 phase->C->set_major_progress(); | |
| 738 } | |
| 739 return RegionNode::Ideal(phase, can_reshape); | |
| 740 } | |
| 741 | |
| 742 | |
| 743 //============================================================================= | |
| 744 //------------------------------Ideal------------------------------------------ | |
| 745 // Return a node which is more "ideal" than the current node. | |
| 746 // Attempt to convert into a counted-loop. | |
| 747 Node *CountedLoopNode::Ideal(PhaseGVN *phase, bool can_reshape) { | |
| 748 return RegionNode::Ideal(phase, can_reshape); | |
| 749 } | |
| 750 | |
| 751 //------------------------------dump_spec-------------------------------------- | |
| 752 // Dump special per-node info | |
| 753 #ifndef PRODUCT | |
| 754 void CountedLoopNode::dump_spec(outputStream *st) const { | |
| 755 LoopNode::dump_spec(st); | |
| 3345 | 756 if (stride_is_con()) { |
| 0 | 757 st->print("stride: %d ",stride_con()); |
| 758 } | |
| 3345 | 759 if (is_pre_loop ()) st->print("pre of N%d" , _main_idx); |
| 760 if (is_main_loop()) st->print("main of N%d", _idx); | |
| 761 if (is_post_loop()) st->print("post of N%d", _main_idx); | |
| 0 | 762 } |
| 763 #endif | |
| 764 | |
| 765 //============================================================================= | |
| 766 int CountedLoopEndNode::stride_con() const { | |
| 767 return stride()->bottom_type()->is_int()->get_con(); | |
| 768 } | |
| 769 | |
| 3345 | 770 //============================================================================= |
| 771 //------------------------------Value----------------------------------------- | |
| 772 const Type *LoopLimitNode::Value( PhaseTransform *phase ) const { | |
| 773 const Type* init_t = phase->type(in(Init)); | |
| 774 const Type* limit_t = phase->type(in(Limit)); | |
| 775 const Type* stride_t = phase->type(in(Stride)); | |
| 776 // Either input is TOP ==> the result is TOP | |
| 777 if (init_t == Type::TOP) return Type::TOP; | |
| 778 if (limit_t == Type::TOP) return Type::TOP; | |
| 779 if (stride_t == Type::TOP) return Type::TOP; | |
| 780 | |
| 781 int stride_con = stride_t->is_int()->get_con(); | |
| 782 if (stride_con == 1) | |
| 783 return NULL; // Identity | |
| 784 | |
| 785 if (init_t->is_int()->is_con() && limit_t->is_int()->is_con()) { | |
| 786 // Use longs to avoid integer overflow. | |
| 787 long init_con = init_t->is_int()->get_con(); | |
| 788 long limit_con = limit_t->is_int()->get_con(); | |
| 789 int stride_m = stride_con - (stride_con > 0 ? 1 : -1); | |
| 790 long trip_count = (limit_con - init_con + stride_m)/stride_con; | |
| 791 long final_con = init_con + stride_con*trip_count; | |
| 792 int final_int = (int)final_con; | |
| 793 // The final value should be in integer range since the loop | |
| 794 // is counted and the limit was checked for overflow. | |
| 795 assert(final_con == (long)final_int, "final value should be integer"); | |
| 796 return TypeInt::make(final_int); | |
| 797 } | |
| 798 | |
| 799 return bottom_type(); // TypeInt::INT | |
| 800 } | |
| 801 | |
| 802 //------------------------------Ideal------------------------------------------ | |
| 803 // Return a node which is more "ideal" than the current node. | |
| 804 Node *LoopLimitNode::Ideal(PhaseGVN *phase, bool can_reshape) { | |
| 805 if (phase->type(in(Init)) == Type::TOP || | |
| 806 phase->type(in(Limit)) == Type::TOP || | |
| 807 phase->type(in(Stride)) == Type::TOP) | |
| 808 return NULL; // Dead | |
| 809 | |
| 810 int stride_con = phase->type(in(Stride))->is_int()->get_con(); | |
| 811 if (stride_con == 1) | |
| 812 return NULL; // Identity | |
| 813 | |
| 814 if (in(Init)->is_Con() && in(Limit)->is_Con()) | |
| 815 return NULL; // Value | |
| 816 | |
| 817 // Delay following optimizations until all loop optimizations | |
| 818 // done to keep Ideal graph simple. | |
| 819 if (!can_reshape || phase->C->major_progress()) | |
| 820 return NULL; | |
| 821 | |
| 822 const TypeInt* init_t = phase->type(in(Init) )->is_int(); | |
| 823 const TypeInt* limit_t = phase->type(in(Limit))->is_int(); | |
| 824 int stride_p; | |
| 825 long lim, ini; | |
| 826 julong max; | |
| 827 if (stride_con > 0) { | |
| 828 stride_p = stride_con; | |
| 829 lim = limit_t->_hi; | |
| 830 ini = init_t->_lo; | |
| 831 max = (julong)max_jint; | |
| 832 } else { | |
| 833 stride_p = -stride_con; | |
| 834 lim = init_t->_hi; | |
| 835 ini = limit_t->_lo; | |
| 836 max = (julong)min_jint; | |
| 837 } | |
| 838 julong range = lim - ini + stride_p; | |
| 839 if (range <= max) { | |
| 840 // Convert to integer expression if it is not overflow. | |
| 841 Node* stride_m = phase->intcon(stride_con - (stride_con > 0 ? 1 : -1)); | |
| 842 Node *range = phase->transform(new (phase->C, 3) SubINode(in(Limit), in(Init))); | |
| 843 Node *bias = phase->transform(new (phase->C, 3) AddINode(range, stride_m)); | |
| 844 Node *trip = phase->transform(new (phase->C, 3) DivINode(0, bias, in(Stride))); | |
| 845 Node *span = phase->transform(new (phase->C, 3) MulINode(trip, in(Stride))); | |
| 846 return new (phase->C, 3) AddINode(span, in(Init)); // exact limit | |
| 847 } | |
| 848 | |
| 849 if (is_power_of_2(stride_p) || // divisor is 2^n | |
| 850 !Matcher::has_match_rule(Op_LoopLimit)) { // or no specialized Mach node? | |
| 851 // Convert to long expression to avoid integer overflow | |
| 852 // and let igvn optimizer convert this division. | |
| 853 // | |
| 854 Node* init = phase->transform( new (phase->C, 2) ConvI2LNode(in(Init))); | |
| 855 Node* limit = phase->transform( new (phase->C, 2) ConvI2LNode(in(Limit))); | |
| 856 Node* stride = phase->longcon(stride_con); | |
| 857 Node* stride_m = phase->longcon(stride_con - (stride_con > 0 ? 1 : -1)); | |
| 858 | |
| 859 Node *range = phase->transform(new (phase->C, 3) SubLNode(limit, init)); | |
| 860 Node *bias = phase->transform(new (phase->C, 3) AddLNode(range, stride_m)); | |
| 861 Node *span; | |
| 862 if (stride_con > 0 && is_power_of_2(stride_p)) { | |
| 863 // bias >= 0 if stride >0, so if stride is 2^n we can use &(-stride) | |
| 864 // and avoid generating rounding for division. Zero trip guard should | |
| 865 // guarantee that init < limit but sometimes the guard is missing and | |
| 866 // we can get situation when init > limit. Note, for the empty loop | |
| 867 // optimization zero trip guard is generated explicitly which leaves | |
| 868 // only RCE predicate where exact limit is used and the predicate | |
| 869 // will simply fail forcing recompilation. | |
| 870 Node* neg_stride = phase->longcon(-stride_con); | |
| 871 span = phase->transform(new (phase->C, 3) AndLNode(bias, neg_stride)); | |
| 872 } else { | |
| 873 Node *trip = phase->transform(new (phase->C, 3) DivLNode(0, bias, stride)); | |
| 874 span = phase->transform(new (phase->C, 3) MulLNode(trip, stride)); | |
| 875 } | |
| 876 // Convert back to int | |
| 877 Node *span_int = phase->transform(new (phase->C, 2) ConvL2INode(span)); | |
| 878 return new (phase->C, 3) AddINode(span_int, in(Init)); // exact limit | |
| 879 } | |
| 880 | |
| 881 return NULL; // No progress | |
| 882 } | |
| 883 | |
| 884 //------------------------------Identity--------------------------------------- | |
| 885 // If stride == 1 return limit node. | |
| 886 Node *LoopLimitNode::Identity( PhaseTransform *phase ) { | |
| 887 int stride_con = phase->type(in(Stride))->is_int()->get_con(); | |
| 888 if (stride_con == 1 || stride_con == -1) | |
| 889 return in(Limit); | |
| 890 return this; | |
| 891 } | |
| 892 | |
| 893 //============================================================================= | |
| 0 | 894 //----------------------match_incr_with_optional_truncation-------------------- |
| 895 // Match increment with optional truncation: | |
| 896 // CHAR: (i+1)&0x7fff, BYTE: ((i+1)<<8)>>8, or SHORT: ((i+1)<<16)>>16 | |
| 897 // Return NULL for failure. Success returns the increment node. | |
| 898 Node* CountedLoopNode::match_incr_with_optional_truncation( | |
| 899 Node* expr, Node** trunc1, Node** trunc2, const TypeInt** trunc_type) { | |
| 900 // Quick cutouts: | |
| 901 if (expr == NULL || expr->req() != 3) return false; | |
| 902 | |
| 903 Node *t1 = NULL; | |
| 904 Node *t2 = NULL; | |
| 905 const TypeInt* trunc_t = TypeInt::INT; | |
| 906 Node* n1 = expr; | |
| 907 int n1op = n1->Opcode(); | |
| 908 | |
| 909 // Try to strip (n1 & M) or (n1 << N >> N) from n1. | |
| 910 if (n1op == Op_AndI && | |
| 911 n1->in(2)->is_Con() && | |
| 912 n1->in(2)->bottom_type()->is_int()->get_con() == 0x7fff) { | |
| 913 // %%% This check should match any mask of 2**K-1. | |
| 914 t1 = n1; | |
| 915 n1 = t1->in(1); | |
| 916 n1op = n1->Opcode(); | |
| 917 trunc_t = TypeInt::CHAR; | |
| 918 } else if (n1op == Op_RShiftI && | |
| 919 n1->in(1) != NULL && | |
| 920 n1->in(1)->Opcode() == Op_LShiftI && | |
| 921 n1->in(2) == n1->in(1)->in(2) && | |
| 922 n1->in(2)->is_Con()) { | |
| 923 jint shift = n1->in(2)->bottom_type()->is_int()->get_con(); | |
| 924 // %%% This check should match any shift in [1..31]. | |
| 925 if (shift == 16 || shift == 8) { | |
| 926 t1 = n1; | |
| 927 t2 = t1->in(1); | |
| 928 n1 = t2->in(1); | |
| 929 n1op = n1->Opcode(); | |
| 930 if (shift == 16) { | |
| 931 trunc_t = TypeInt::SHORT; | |
| 932 } else if (shift == 8) { | |
| 933 trunc_t = TypeInt::BYTE; | |
| 934 } | |
| 935 } | |
| 936 } | |
| 937 | |
| 938 // If (maybe after stripping) it is an AddI, we won: | |
| 939 if (n1op == Op_AddI) { | |
| 940 *trunc1 = t1; | |
| 941 *trunc2 = t2; | |
| 942 *trunc_type = trunc_t; | |
| 943 return n1; | |
| 944 } | |
| 945 | |
| 946 // failed | |
| 947 return NULL; | |
| 948 } | |
| 949 | |
| 950 | |
| 951 //------------------------------filtered_type-------------------------------- | |
| 952 // Return a type based on condition control flow | |
| 953 // A successful return will be a type that is restricted due | |
| 954 // to a series of dominating if-tests, such as: | |
| 955 // if (i < 10) { | |
| 956 // if (i > 0) { | |
| 957 // here: "i" type is [1..10) | |
| 958 // } | |
| 959 // } | |
| 960 // or a control flow merge | |
| 961 // if (i < 10) { | |
| 962 // do { | |
| 963 // phi( , ) -- at top of loop type is [min_int..10) | |
| 964 // i = ? | |
| 965 // } while ( i < 10) | |
| 966 // | |
| 967 const TypeInt* PhaseIdealLoop::filtered_type( Node *n, Node* n_ctrl) { | |
| 968 assert(n && n->bottom_type()->is_int(), "must be int"); | |
| 969 const TypeInt* filtered_t = NULL; | |
| 970 if (!n->is_Phi()) { | |
| 971 assert(n_ctrl != NULL || n_ctrl == C->top(), "valid control"); | |
| 972 filtered_t = filtered_type_from_dominators(n, n_ctrl); | |
| 973 | |
| 974 } else { | |
| 975 Node* phi = n->as_Phi(); | |
| 976 Node* region = phi->in(0); | |
| 977 assert(n_ctrl == NULL || n_ctrl == region, "ctrl parameter must be region"); | |
| 978 if (region && region != C->top()) { | |
| 979 for (uint i = 1; i < phi->req(); i++) { | |
| 980 Node* val = phi->in(i); | |
| 981 Node* use_c = region->in(i); | |
| 982 const TypeInt* val_t = filtered_type_from_dominators(val, use_c); | |
| 983 if (val_t != NULL) { | |
| 984 if (filtered_t == NULL) { | |
| 985 filtered_t = val_t; | |
| 986 } else { | |
| 987 filtered_t = filtered_t->meet(val_t)->is_int(); | |
| 988 } | |
| 989 } | |
| 990 } | |
| 991 } | |
| 992 } | |
| 993 const TypeInt* n_t = _igvn.type(n)->is_int(); | |
| 994 if (filtered_t != NULL) { | |
| 995 n_t = n_t->join(filtered_t)->is_int(); | |
| 996 } | |
| 997 return n_t; | |
| 998 } | |
| 999 | |
| 1000 | |
| 1001 //------------------------------filtered_type_from_dominators-------------------------------- | |
| 1002 // Return a possibly more restrictive type for val based on condition control flow of dominators | |
| 1003 const TypeInt* PhaseIdealLoop::filtered_type_from_dominators( Node* val, Node *use_ctrl) { | |
| 1004 if (val->is_Con()) { | |
| 1005 return val->bottom_type()->is_int(); | |
| 1006 } | |
| 1007 uint if_limit = 10; // Max number of dominating if's visited | |
| 1008 const TypeInt* rtn_t = NULL; | |
| 1009 | |
| 1010 if (use_ctrl && use_ctrl != C->top()) { | |
| 1011 Node* val_ctrl = get_ctrl(val); | |
| 1012 uint val_dom_depth = dom_depth(val_ctrl); | |
| 1013 Node* pred = use_ctrl; | |
| 1014 uint if_cnt = 0; | |
| 1015 while (if_cnt < if_limit) { | |
| 1016 if ((pred->Opcode() == Op_IfTrue || pred->Opcode() == Op_IfFalse)) { | |
| 1017 if_cnt++; | |
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1018 const TypeInt* if_t = IfNode::filtered_int_type(&_igvn, val, pred); |
| 0 | 1019 if (if_t != NULL) { |
| 1020 if (rtn_t == NULL) { | |
| 1021 rtn_t = if_t; | |
| 1022 } else { | |
| 1023 rtn_t = rtn_t->join(if_t)->is_int(); | |
| 1024 } | |
| 1025 } | |
| 1026 } | |
| 1027 pred = idom(pred); | |
| 1028 if (pred == NULL || pred == C->top()) { | |
| 1029 break; | |
| 1030 } | |
| 1031 // Stop if going beyond definition block of val | |
| 1032 if (dom_depth(pred) < val_dom_depth) { | |
| 1033 break; | |
| 1034 } | |
| 1035 } | |
| 1036 } | |
| 1037 return rtn_t; | |
| 1038 } | |
| 1039 | |
| 1040 | |
| 1041 //------------------------------dump_spec-------------------------------------- | |
| 1042 // Dump special per-node info | |
| 1043 #ifndef PRODUCT | |
| 1044 void CountedLoopEndNode::dump_spec(outputStream *st) const { | |
| 1045 if( in(TestValue)->is_Bool() ) { | |
| 1046 BoolTest bt( test_trip()); // Added this for g++. | |
| 1047 | |
| 1048 st->print("["); | |
| 1049 bt.dump_on(st); | |
| 1050 st->print("]"); | |
| 1051 } | |
| 1052 st->print(" "); | |
| 1053 IfNode::dump_spec(st); | |
| 1054 } | |
| 1055 #endif | |
| 1056 | |
| 1057 //============================================================================= | |
| 1058 //------------------------------is_member-------------------------------------- | |
| 1059 // Is 'l' a member of 'this'? | |
| 1060 int IdealLoopTree::is_member( const IdealLoopTree *l ) const { | |
| 1061 while( l->_nest > _nest ) l = l->_parent; | |
| 1062 return l == this; | |
| 1063 } | |
| 1064 | |
| 1065 //------------------------------set_nest--------------------------------------- | |
| 1066 // Set loop tree nesting depth. Accumulate _has_call bits. | |
| 1067 int IdealLoopTree::set_nest( uint depth ) { | |
| 1068 _nest = depth; | |
| 1069 int bits = _has_call; | |
| 1070 if( _child ) bits |= _child->set_nest(depth+1); | |
| 1071 if( bits ) _has_call = 1; | |
| 1072 if( _next ) bits |= _next ->set_nest(depth ); | |
| 1073 return bits; | |
| 1074 } | |
| 1075 | |
| 1076 //------------------------------split_fall_in---------------------------------- | |
| 1077 // Split out multiple fall-in edges from the loop header. Move them to a | |
| 1078 // private RegionNode before the loop. This becomes the loop landing pad. | |
| 1079 void IdealLoopTree::split_fall_in( PhaseIdealLoop *phase, int fall_in_cnt ) { | |
| 1080 PhaseIterGVN &igvn = phase->_igvn; | |
| 1081 uint i; | |
| 1082 | |
| 1083 // Make a new RegionNode to be the landing pad. | |
| 1084 Node *landing_pad = new (phase->C, fall_in_cnt+1) RegionNode( fall_in_cnt+1 ); | |
| 1085 phase->set_loop(landing_pad,_parent); | |
| 1086 // Gather all the fall-in control paths into the landing pad | |
| 1087 uint icnt = fall_in_cnt; | |
| 1088 uint oreq = _head->req(); | |
| 1089 for( i = oreq-1; i>0; i-- ) | |
| 1090 if( !phase->is_member( this, _head->in(i) ) ) | |
| 1091 landing_pad->set_req(icnt--,_head->in(i)); | |
| 1092 | |
| 1093 // Peel off PhiNode edges as well | |
| 1094 for (DUIterator_Fast jmax, j = _head->fast_outs(jmax); j < jmax; j++) { | |
| 1095 Node *oj = _head->fast_out(j); | |
| 1096 if( oj->is_Phi() ) { | |
| 1097 PhiNode* old_phi = oj->as_Phi(); | |
| 1098 assert( old_phi->region() == _head, "" ); | |
| 1099 igvn.hash_delete(old_phi); // Yank from hash before hacking edges | |
| 1100 Node *p = PhiNode::make_blank(landing_pad, old_phi); | |
| 1101 uint icnt = fall_in_cnt; | |
| 1102 for( i = oreq-1; i>0; i-- ) { | |
| 1103 if( !phase->is_member( this, _head->in(i) ) ) { | |
| 1104 p->init_req(icnt--, old_phi->in(i)); | |
| 1105 // Go ahead and clean out old edges from old phi | |
| 1106 old_phi->del_req(i); | |
| 1107 } | |
| 1108 } | |
| 1109 // Search for CSE's here, because ZKM.jar does a lot of | |
| 1110 // loop hackery and we need to be a little incremental | |
| 1111 // with the CSE to avoid O(N^2) node blow-up. | |
| 1112 Node *p2 = igvn.hash_find_insert(p); // Look for a CSE | |
| 1113 if( p2 ) { // Found CSE | |
| 1114 p->destruct(); // Recover useless new node | |
| 1115 p = p2; // Use old node | |
| 1116 } else { | |
| 1117 igvn.register_new_node_with_optimizer(p, old_phi); | |
| 1118 } | |
| 1119 // Make old Phi refer to new Phi. | |
| 1120 old_phi->add_req(p); | |
| 1121 // Check for the special case of making the old phi useless and | |
| 1122 // disappear it. In JavaGrande I have a case where this useless | |
| 1123 // Phi is the loop limit and prevents recognizing a CountedLoop | |
| 1124 // which in turn prevents removing an empty loop. | |
| 1125 Node *id_old_phi = old_phi->Identity( &igvn ); | |
| 1126 if( id_old_phi != old_phi ) { // Found a simple identity? | |
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1127 // Note that I cannot call 'replace_node' here, because |
| 0 | 1128 // that will yank the edge from old_phi to the Region and |
| 1129 // I'm mid-iteration over the Region's uses. | |
| 1130 for (DUIterator_Last imin, i = old_phi->last_outs(imin); i >= imin; ) { | |
| 1131 Node* use = old_phi->last_out(i); | |
| 1132 igvn.hash_delete(use); | |
| 1133 igvn._worklist.push(use); | |
| 1134 uint uses_found = 0; | |
| 1135 for (uint j = 0; j < use->len(); j++) { | |
| 1136 if (use->in(j) == old_phi) { | |
| 1137 if (j < use->req()) use->set_req (j, id_old_phi); | |
| 1138 else use->set_prec(j, id_old_phi); | |
| 1139 uses_found++; | |
| 1140 } | |
| 1141 } | |
| 1142 i -= uses_found; // we deleted 1 or more copies of this edge | |
| 1143 } | |
| 1144 } | |
| 1145 igvn._worklist.push(old_phi); | |
| 1146 } | |
| 1147 } | |
| 1148 // Finally clean out the fall-in edges from the RegionNode | |
| 1149 for( i = oreq-1; i>0; i-- ) { | |
| 1150 if( !phase->is_member( this, _head->in(i) ) ) { | |
| 1151 _head->del_req(i); | |
| 1152 } | |
| 1153 } | |
| 1154 // Transform landing pad | |
| 1155 igvn.register_new_node_with_optimizer(landing_pad, _head); | |
| 1156 // Insert landing pad into the header | |
| 1157 _head->add_req(landing_pad); | |
| 1158 } | |
| 1159 | |
| 1160 //------------------------------split_outer_loop------------------------------- | |
| 1161 // Split out the outermost loop from this shared header. | |
| 1162 void IdealLoopTree::split_outer_loop( PhaseIdealLoop *phase ) { | |
| 1163 PhaseIterGVN &igvn = phase->_igvn; | |
| 1164 | |
| 1165 // Find index of outermost loop; it should also be my tail. | |
| 1166 uint outer_idx = 1; | |
| 1167 while( _head->in(outer_idx) != _tail ) outer_idx++; | |
| 1168 | |
| 1169 // Make a LoopNode for the outermost loop. | |
| 1170 Node *ctl = _head->in(LoopNode::EntryControl); | |
| 1171 Node *outer = new (phase->C, 3) LoopNode( ctl, _head->in(outer_idx) ); | |
| 1172 outer = igvn.register_new_node_with_optimizer(outer, _head); | |
| 1173 phase->set_created_loop_node(); | |
| 2445 | 1174 |
| 0 | 1175 // Outermost loop falls into '_head' loop |
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1176 _head->set_req(LoopNode::EntryControl, outer); |
| 0 | 1177 _head->del_req(outer_idx); |
| 1178 // Split all the Phis up between '_head' loop and 'outer' loop. | |
| 1179 for (DUIterator_Fast jmax, j = _head->fast_outs(jmax); j < jmax; j++) { | |
| 1180 Node *out = _head->fast_out(j); | |
| 1181 if( out->is_Phi() ) { | |
| 1182 PhiNode *old_phi = out->as_Phi(); | |
| 1183 assert( old_phi->region() == _head, "" ); | |
| 1184 Node *phi = PhiNode::make_blank(outer, old_phi); | |
| 1185 phi->init_req(LoopNode::EntryControl, old_phi->in(LoopNode::EntryControl)); | |
| 1186 phi->init_req(LoopNode::LoopBackControl, old_phi->in(outer_idx)); | |
| 1187 phi = igvn.register_new_node_with_optimizer(phi, old_phi); | |
| 1188 // Make old Phi point to new Phi on the fall-in path | |
| 1189 igvn.hash_delete(old_phi); | |
| 1190 old_phi->set_req(LoopNode::EntryControl, phi); | |
| 1191 old_phi->del_req(outer_idx); | |
| 1192 igvn._worklist.push(old_phi); | |
| 1193 } | |
| 1194 } | |
| 1195 | |
| 1196 // Use the new loop head instead of the old shared one | |
| 1197 _head = outer; | |
| 1198 phase->set_loop(_head, this); | |
| 1199 } | |
| 1200 | |
| 1201 //------------------------------fix_parent------------------------------------- | |
| 1202 static void fix_parent( IdealLoopTree *loop, IdealLoopTree *parent ) { | |
| 1203 loop->_parent = parent; | |
| 1204 if( loop->_child ) fix_parent( loop->_child, loop ); | |
| 1205 if( loop->_next ) fix_parent( loop->_next , parent ); | |
| 1206 } | |
| 1207 | |
| 1208 //------------------------------estimate_path_freq----------------------------- | |
| 1209 static float estimate_path_freq( Node *n ) { | |
| 1210 // Try to extract some path frequency info | |
| 1211 IfNode *iff; | |
| 1212 for( int i = 0; i < 50; i++ ) { // Skip through a bunch of uncommon tests | |
| 1213 uint nop = n->Opcode(); | |
| 1214 if( nop == Op_SafePoint ) { // Skip any safepoint | |
| 1215 n = n->in(0); | |
| 1216 continue; | |
| 1217 } | |
| 1218 if( nop == Op_CatchProj ) { // Get count from a prior call | |
| 1219 // Assume call does not always throw exceptions: means the call-site | |
| 1220 // count is also the frequency of the fall-through path. | |
| 1221 assert( n->is_CatchProj(), "" ); | |
| 1222 if( ((CatchProjNode*)n)->_con != CatchProjNode::fall_through_index ) | |
| 1223 return 0.0f; // Assume call exception path is rare | |
| 1224 Node *call = n->in(0)->in(0)->in(0); | |
| 1225 assert( call->is_Call(), "expect a call here" ); | |
| 1226 const JVMState *jvms = ((CallNode*)call)->jvms(); | |
| 1227 ciMethodData* methodData = jvms->method()->method_data(); | |
| 1228 if (!methodData->is_mature()) return 0.0f; // No call-site data | |
| 1229 ciProfileData* data = methodData->bci_to_data(jvms->bci()); | |
| 1230 if ((data == NULL) || !data->is_CounterData()) { | |
| 1231 // no call profile available, try call's control input | |
| 1232 n = n->in(0); | |
| 1233 continue; | |
| 1234 } | |
| 1235 return data->as_CounterData()->count()/FreqCountInvocations; | |
| 1236 } | |
| 1237 // See if there's a gating IF test | |
| 1238 Node *n_c = n->in(0); | |
| 1239 if( !n_c->is_If() ) break; // No estimate available | |
| 1240 iff = n_c->as_If(); | |
| 1241 if( iff->_fcnt != COUNT_UNKNOWN ) // Have a valid count? | |
| 1242 // Compute how much count comes on this path | |
| 1243 return ((nop == Op_IfTrue) ? iff->_prob : 1.0f - iff->_prob) * iff->_fcnt; | |
| 1244 // Have no count info. Skip dull uncommon-trap like branches. | |
| 1245 if( (nop == Op_IfTrue && iff->_prob < PROB_LIKELY_MAG(5)) || | |
| 1246 (nop == Op_IfFalse && iff->_prob > PROB_UNLIKELY_MAG(5)) ) | |
| 1247 break; | |
| 1248 // Skip through never-taken branch; look for a real loop exit. | |
| 1249 n = iff->in(0); | |
| 1250 } | |
| 1251 return 0.0f; // No estimate available | |
| 1252 } | |
| 1253 | |
| 1254 //------------------------------merge_many_backedges--------------------------- | |
| 1255 // Merge all the backedges from the shared header into a private Region. | |
| 1256 // Feed that region as the one backedge to this loop. | |
| 1257 void IdealLoopTree::merge_many_backedges( PhaseIdealLoop *phase ) { | |
| 1258 uint i; | |
| 1259 | |
| 1260 // Scan for the top 2 hottest backedges | |
| 1261 float hotcnt = 0.0f; | |
| 1262 float warmcnt = 0.0f; | |
| 1263 uint hot_idx = 0; | |
| 1264 // Loop starts at 2 because slot 1 is the fall-in path | |
| 1265 for( i = 2; i < _head->req(); i++ ) { | |
| 1266 float cnt = estimate_path_freq(_head->in(i)); | |
| 1267 if( cnt > hotcnt ) { // Grab hottest path | |
| 1268 warmcnt = hotcnt; | |
| 1269 hotcnt = cnt; | |
| 1270 hot_idx = i; | |
| 1271 } else if( cnt > warmcnt ) { // And 2nd hottest path | |
| 1272 warmcnt = cnt; | |
| 1273 } | |
| 1274 } | |
| 1275 | |
| 1276 // See if the hottest backedge is worthy of being an inner loop | |
| 1277 // by being much hotter than the next hottest backedge. | |
| 1278 if( hotcnt <= 0.0001 || | |
| 1279 hotcnt < 2.0*warmcnt ) hot_idx = 0;// No hot backedge | |
| 1280 | |
| 1281 // Peel out the backedges into a private merge point; peel | |
| 1282 // them all except optionally hot_idx. | |
| 1283 PhaseIterGVN &igvn = phase->_igvn; | |
| 1284 | |
| 1285 Node *hot_tail = NULL; | |
| 1286 // Make a Region for the merge point | |
| 1287 Node *r = new (phase->C, 1) RegionNode(1); | |
| 1288 for( i = 2; i < _head->req(); i++ ) { | |
| 1289 if( i != hot_idx ) | |
| 1290 r->add_req( _head->in(i) ); | |
| 1291 else hot_tail = _head->in(i); | |
| 1292 } | |
| 1293 igvn.register_new_node_with_optimizer(r, _head); | |
| 1294 // Plug region into end of loop _head, followed by hot_tail | |
| 1295 while( _head->req() > 3 ) _head->del_req( _head->req()-1 ); | |
| 1296 _head->set_req(2, r); | |
| 1297 if( hot_idx ) _head->add_req(hot_tail); | |
| 1298 | |
| 1299 // Split all the Phis up between '_head' loop and the Region 'r' | |
| 1300 for (DUIterator_Fast jmax, j = _head->fast_outs(jmax); j < jmax; j++) { | |
| 1301 Node *out = _head->fast_out(j); | |
| 1302 if( out->is_Phi() ) { | |
| 1303 PhiNode* n = out->as_Phi(); | |
| 1304 igvn.hash_delete(n); // Delete from hash before hacking edges | |
| 1305 Node *hot_phi = NULL; | |
| 1306 Node *phi = new (phase->C, r->req()) PhiNode(r, n->type(), n->adr_type()); | |
| 1307 // Check all inputs for the ones to peel out | |
| 1308 uint j = 1; | |
| 1309 for( uint i = 2; i < n->req(); i++ ) { | |
| 1310 if( i != hot_idx ) | |
| 1311 phi->set_req( j++, n->in(i) ); | |
| 1312 else hot_phi = n->in(i); | |
| 1313 } | |
| 1314 // Register the phi but do not transform until whole place transforms | |
| 1315 igvn.register_new_node_with_optimizer(phi, n); | |
| 1316 // Add the merge phi to the old Phi | |
| 1317 while( n->req() > 3 ) n->del_req( n->req()-1 ); | |
| 1318 n->set_req(2, phi); | |
| 1319 if( hot_idx ) n->add_req(hot_phi); | |
| 1320 } | |
| 1321 } | |
| 1322 | |
| 1323 | |
| 1324 // Insert a new IdealLoopTree inserted below me. Turn it into a clone | |
| 1325 // of self loop tree. Turn self into a loop headed by _head and with | |
| 1326 // tail being the new merge point. | |
| 1327 IdealLoopTree *ilt = new IdealLoopTree( phase, _head, _tail ); | |
| 1328 phase->set_loop(_tail,ilt); // Adjust tail | |
| 1329 _tail = r; // Self's tail is new merge point | |
| 1330 phase->set_loop(r,this); | |
| 1331 ilt->_child = _child; // New guy has my children | |
| 1332 _child = ilt; // Self has new guy as only child | |
| 1333 ilt->_parent = this; // new guy has self for parent | |
| 1334 ilt->_nest = _nest; // Same nesting depth (for now) | |
| 1335 | |
| 1336 // Starting with 'ilt', look for child loop trees using the same shared | |
| 1337 // header. Flatten these out; they will no longer be loops in the end. | |
| 1338 IdealLoopTree **pilt = &_child; | |
| 1339 while( ilt ) { | |
| 1340 if( ilt->_head == _head ) { | |
| 1341 uint i; | |
| 1342 for( i = 2; i < _head->req(); i++ ) | |
| 1343 if( _head->in(i) == ilt->_tail ) | |
| 1344 break; // Still a loop | |
| 1345 if( i == _head->req() ) { // No longer a loop | |
| 1346 // Flatten ilt. Hang ilt's "_next" list from the end of | |
| 1347 // ilt's '_child' list. Move the ilt's _child up to replace ilt. | |
| 1348 IdealLoopTree **cp = &ilt->_child; | |
| 1349 while( *cp ) cp = &(*cp)->_next; // Find end of child list | |
| 1350 *cp = ilt->_next; // Hang next list at end of child list | |
| 1351 *pilt = ilt->_child; // Move child up to replace ilt | |
| 1352 ilt->_head = NULL; // Flag as a loop UNIONED into parent | |
| 1353 ilt = ilt->_child; // Repeat using new ilt | |
| 1354 continue; // do not advance over ilt->_child | |
| 1355 } | |
| 1356 assert( ilt->_tail == hot_tail, "expected to only find the hot inner loop here" ); | |
| 1357 phase->set_loop(_head,ilt); | |
| 1358 } | |
| 1359 pilt = &ilt->_child; // Advance to next | |
| 1360 ilt = *pilt; | |
| 1361 } | |
| 1362 | |
| 1363 if( _child ) fix_parent( _child, this ); | |
| 1364 } | |
| 1365 | |
| 1366 //------------------------------beautify_loops--------------------------------- | |
| 1367 // Split shared headers and insert loop landing pads. | |
| 1368 // Insert a LoopNode to replace the RegionNode. | |
| 1369 // Return TRUE if loop tree is structurally changed. | |
| 1370 bool IdealLoopTree::beautify_loops( PhaseIdealLoop *phase ) { | |
| 1371 bool result = false; | |
| 1372 // Cache parts in locals for easy | |
| 1373 PhaseIterGVN &igvn = phase->_igvn; | |
| 1374 | |
| 1375 igvn.hash_delete(_head); // Yank from hash before hacking edges | |
| 1376 | |
| 1377 // Check for multiple fall-in paths. Peel off a landing pad if need be. | |
| 1378 int fall_in_cnt = 0; | |
| 1379 for( uint i = 1; i < _head->req(); i++ ) | |
| 1380 if( !phase->is_member( this, _head->in(i) ) ) | |
| 1381 fall_in_cnt++; | |
| 1382 assert( fall_in_cnt, "at least 1 fall-in path" ); | |
| 1383 if( fall_in_cnt > 1 ) // Need a loop landing pad to merge fall-ins | |
| 1384 split_fall_in( phase, fall_in_cnt ); | |
| 1385 | |
| 1386 // Swap inputs to the _head and all Phis to move the fall-in edge to | |
| 1387 // the left. | |
| 1388 fall_in_cnt = 1; | |
| 1389 while( phase->is_member( this, _head->in(fall_in_cnt) ) ) | |
| 1390 fall_in_cnt++; | |
| 1391 if( fall_in_cnt > 1 ) { | |
| 1392 // Since I am just swapping inputs I do not need to update def-use info | |
| 1393 Node *tmp = _head->in(1); | |
| 1394 _head->set_req( 1, _head->in(fall_in_cnt) ); | |
| 1395 _head->set_req( fall_in_cnt, tmp ); | |
| 1396 // Swap also all Phis | |
| 1397 for (DUIterator_Fast imax, i = _head->fast_outs(imax); i < imax; i++) { | |
| 1398 Node* phi = _head->fast_out(i); | |
| 1399 if( phi->is_Phi() ) { | |
| 1400 igvn.hash_delete(phi); // Yank from hash before hacking edges | |
| 1401 tmp = phi->in(1); | |
| 1402 phi->set_req( 1, phi->in(fall_in_cnt) ); | |
| 1403 phi->set_req( fall_in_cnt, tmp ); | |
| 1404 } | |
| 1405 } | |
| 1406 } | |
| 1407 assert( !phase->is_member( this, _head->in(1) ), "left edge is fall-in" ); | |
| 1408 assert( phase->is_member( this, _head->in(2) ), "right edge is loop" ); | |
| 1409 | |
| 1410 // If I am a shared header (multiple backedges), peel off the many | |
| 1411 // backedges into a private merge point and use the merge point as | |
| 1412 // the one true backedge. | |
| 1413 if( _head->req() > 3 ) { | |
| 2445 | 1414 // Merge the many backedges into a single backedge but leave |
| 1415 // the hottest backedge as separate edge for the following peel. | |
| 0 | 1416 merge_many_backedges( phase ); |
| 1417 result = true; | |
| 1418 } | |
| 1419 | |
| 2445 | 1420 // If I have one hot backedge, peel off myself loop. |
| 0 | 1421 // I better be the outermost loop. |
| 1422 if( _head->req() > 3 ) { | |
| 1423 split_outer_loop( phase ); | |
| 1424 result = true; | |
| 1425 | |
| 1426 } else if( !_head->is_Loop() && !_irreducible ) { | |
| 1427 // Make a new LoopNode to replace the old loop head | |
| 1428 Node *l = new (phase->C, 3) LoopNode( _head->in(1), _head->in(2) ); | |
| 1429 l = igvn.register_new_node_with_optimizer(l, _head); | |
| 1430 phase->set_created_loop_node(); | |
| 1431 // Go ahead and replace _head | |
|
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1432 phase->_igvn.replace_node( _head, l ); |
| 0 | 1433 _head = l; |
| 1434 phase->set_loop(_head, this); | |
| 1435 } | |
| 1436 | |
| 1437 // Now recursively beautify nested loops | |
| 1438 if( _child ) result |= _child->beautify_loops( phase ); | |
| 1439 if( _next ) result |= _next ->beautify_loops( phase ); | |
| 1440 return result; | |
| 1441 } | |
| 1442 | |
| 1443 //------------------------------allpaths_check_safepts---------------------------- | |
| 1444 // Allpaths backwards scan from loop tail, terminating each path at first safepoint | |
| 1445 // encountered. Helper for check_safepts. | |
| 1446 void IdealLoopTree::allpaths_check_safepts(VectorSet &visited, Node_List &stack) { | |
| 1447 assert(stack.size() == 0, "empty stack"); | |
| 1448 stack.push(_tail); | |
| 1449 visited.Clear(); | |
| 1450 visited.set(_tail->_idx); | |
| 1451 while (stack.size() > 0) { | |
| 1452 Node* n = stack.pop(); | |
| 1453 if (n->is_Call() && n->as_Call()->guaranteed_safepoint()) { | |
| 1454 // Terminate this path | |
| 1455 } else if (n->Opcode() == Op_SafePoint) { | |
| 1456 if (_phase->get_loop(n) != this) { | |
| 1457 if (_required_safept == NULL) _required_safept = new Node_List(); | |
| 1458 _required_safept->push(n); // save the one closest to the tail | |
| 1459 } | |
| 1460 // Terminate this path | |
| 1461 } else { | |
| 1462 uint start = n->is_Region() ? 1 : 0; | |
| 1463 uint end = n->is_Region() && !n->is_Loop() ? n->req() : start + 1; | |
| 1464 for (uint i = start; i < end; i++) { | |
| 1465 Node* in = n->in(i); | |
| 1466 assert(in->is_CFG(), "must be"); | |
| 1467 if (!visited.test_set(in->_idx) && is_member(_phase->get_loop(in))) { | |
| 1468 stack.push(in); | |
| 1469 } | |
| 1470 } | |
| 1471 } | |
| 1472 } | |
| 1473 } | |
| 1474 | |
| 1475 //------------------------------check_safepts---------------------------- | |
| 1476 // Given dominators, try to find loops with calls that must always be | |
| 1477 // executed (call dominates loop tail). These loops do not need non-call | |
| 1478 // safepoints (ncsfpt). | |
| 1479 // | |
| 1480 // A complication is that a safepoint in a inner loop may be needed | |
| 1481 // by an outer loop. In the following, the inner loop sees it has a | |
| 1482 // call (block 3) on every path from the head (block 2) to the | |
| 1483 // backedge (arc 3->2). So it deletes the ncsfpt (non-call safepoint) | |
| 1484 // in block 2, _but_ this leaves the outer loop without a safepoint. | |
| 1485 // | |
| 1486 // entry 0 | |
| 1487 // | | |
| 1488 // v | |
| 1489 // outer 1,2 +->1 | |
| 1490 // | | | |
| 1491 // | v | |
| 1492 // | 2<---+ ncsfpt in 2 | |
| 1493 // |_/|\ | | |
| 1494 // | v | | |
| 1495 // inner 2,3 / 3 | call in 3 | |
| 1496 // / | | | |
| 1497 // v +--+ | |
| 1498 // exit 4 | |
| 1499 // | |
| 1500 // | |
| 1501 // This method creates a list (_required_safept) of ncsfpt nodes that must | |
| 1502 // be protected is created for each loop. When a ncsfpt maybe deleted, it | |
| 1503 // is first looked for in the lists for the outer loops of the current loop. | |
| 1504 // | |
| 1505 // The insights into the problem: | |
| 1506 // A) counted loops are okay | |
| 1507 // B) innermost loops are okay (only an inner loop can delete | |
| 1508 // a ncsfpt needed by an outer loop) | |
| 1509 // C) a loop is immune from an inner loop deleting a safepoint | |
| 1510 // if the loop has a call on the idom-path | |
| 1511 // D) a loop is also immune if it has a ncsfpt (non-call safepoint) on the | |
| 1512 // idom-path that is not in a nested loop | |
| 1513 // E) otherwise, an ncsfpt on the idom-path that is nested in an inner | |
| 1514 // loop needs to be prevented from deletion by an inner loop | |
| 1515 // | |
| 1516 // There are two analyses: | |
| 1517 // 1) The first, and cheaper one, scans the loop body from | |
| 1518 // tail to head following the idom (immediate dominator) | |
| 1519 // chain, looking for the cases (C,D,E) above. | |
| 1520 // Since inner loops are scanned before outer loops, there is summary | |
| 1521 // information about inner loops. Inner loops can be skipped over | |
| 1522 // when the tail of an inner loop is encountered. | |
| 1523 // | |
| 1524 // 2) The second, invoked if the first fails to find a call or ncsfpt on | |
| 1525 // the idom path (which is rare), scans all predecessor control paths | |
| 1526 // from the tail to the head, terminating a path when a call or sfpt | |
| 1527 // is encountered, to find the ncsfpt's that are closest to the tail. | |
| 1528 // | |
| 1529 void IdealLoopTree::check_safepts(VectorSet &visited, Node_List &stack) { | |
| 1530 // Bottom up traversal | |
| 1531 IdealLoopTree* ch = _child; | |
| 1532 while (ch != NULL) { | |
| 1533 ch->check_safepts(visited, stack); | |
| 1534 ch = ch->_next; | |
| 1535 } | |
| 1536 | |
| 1537 if (!_head->is_CountedLoop() && !_has_sfpt && _parent != NULL && !_irreducible) { | |
| 1538 bool has_call = false; // call on dom-path | |
| 1539 bool has_local_ncsfpt = false; // ncsfpt on dom-path at this loop depth | |
| 1540 Node* nonlocal_ncsfpt = NULL; // ncsfpt on dom-path at a deeper depth | |
| 1541 // Scan the dom-path nodes from tail to head | |
| 1542 for (Node* n = tail(); n != _head; n = _phase->idom(n)) { | |
| 1543 if (n->is_Call() && n->as_Call()->guaranteed_safepoint()) { | |
| 1544 has_call = true; | |
| 1545 _has_sfpt = 1; // Then no need for a safept! | |
| 1546 break; | |
| 1547 } else if (n->Opcode() == Op_SafePoint) { | |
| 1548 if (_phase->get_loop(n) == this) { | |
| 1549 has_local_ncsfpt = true; | |
| 1550 break; | |
| 1551 } | |
| 1552 if (nonlocal_ncsfpt == NULL) { | |
| 1553 nonlocal_ncsfpt = n; // save the one closest to the tail | |
| 1554 } | |
| 1555 } else { | |
| 1556 IdealLoopTree* nlpt = _phase->get_loop(n); | |
| 1557 if (this != nlpt) { | |
| 1558 // If at an inner loop tail, see if the inner loop has already | |
| 1559 // recorded seeing a call on the dom-path (and stop.) If not, | |
| 1560 // jump to the head of the inner loop. | |
| 1561 assert(is_member(nlpt), "nested loop"); | |
| 1562 Node* tail = nlpt->_tail; | |
| 1563 if (tail->in(0)->is_If()) tail = tail->in(0); | |
| 1564 if (n == tail) { | |
| 1565 // If inner loop has call on dom-path, so does outer loop | |
| 1566 if (nlpt->_has_sfpt) { | |
| 1567 has_call = true; | |
| 1568 _has_sfpt = 1; | |
| 1569 break; | |
| 1570 } | |
| 1571 // Skip to head of inner loop | |
| 1572 assert(_phase->is_dominator(_head, nlpt->_head), "inner head dominated by outer head"); | |
| 1573 n = nlpt->_head; | |
| 1574 } | |
| 1575 } | |
| 1576 } | |
| 1577 } | |
| 1578 // Record safept's that this loop needs preserved when an | |
| 1579 // inner loop attempts to delete it's safepoints. | |
| 1580 if (_child != NULL && !has_call && !has_local_ncsfpt) { | |
| 1581 if (nonlocal_ncsfpt != NULL) { | |
| 1582 if (_required_safept == NULL) _required_safept = new Node_List(); | |
| 1583 _required_safept->push(nonlocal_ncsfpt); | |
| 1584 } else { | |
| 1585 // Failed to find a suitable safept on the dom-path. Now use | |
| 1586 // an all paths walk from tail to head, looking for safepoints to preserve. | |
| 1587 allpaths_check_safepts(visited, stack); | |
| 1588 } | |
| 1589 } | |
| 1590 } | |
| 1591 } | |
| 1592 | |
| 1593 //---------------------------is_deleteable_safept---------------------------- | |
| 1594 // Is safept not required by an outer loop? | |
| 1595 bool PhaseIdealLoop::is_deleteable_safept(Node* sfpt) { | |
| 1596 assert(sfpt->Opcode() == Op_SafePoint, ""); | |
| 1597 IdealLoopTree* lp = get_loop(sfpt)->_parent; | |
| 1598 while (lp != NULL) { | |
| 1599 Node_List* sfpts = lp->_required_safept; | |
| 1600 if (sfpts != NULL) { | |
| 1601 for (uint i = 0; i < sfpts->size(); i++) { | |
| 1602 if (sfpt == sfpts->at(i)) | |
| 1603 return false; | |
| 1604 } | |
| 1605 } | |
| 1606 lp = lp->_parent; | |
| 1607 } | |
| 1608 return true; | |
| 1609 } | |
| 1610 | |
|
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1611 //---------------------------replace_parallel_iv------------------------------- |
|
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1612 // Replace parallel induction variable (parallel to trip counter) |
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1613 void PhaseIdealLoop::replace_parallel_iv(IdealLoopTree *loop) { |
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1614 assert(loop->_head->is_CountedLoop(), ""); |
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1615 CountedLoopNode *cl = loop->_head->as_CountedLoop(); |
|
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1616 if (!cl->is_valid_counted_loop()) |
|
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1617 return; // skip malformed counted loop |
|
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1618 Node *incr = cl->incr(); |
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1619 if (incr == NULL) |
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1620 return; // Dead loop? |
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1621 Node *init = cl->init_trip(); |
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1622 Node *phi = cl->phi(); |
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1623 int stride_con = cl->stride_con(); |
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1624 |
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1625 // Visit all children, looking for Phis |
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1626 for (DUIterator i = cl->outs(); cl->has_out(i); i++) { |
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1627 Node *out = cl->out(i); |
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1628 // Look for other phis (secondary IVs). Skip dead ones |
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1629 if (!out->is_Phi() || out == phi || !has_node(out)) |
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1630 continue; |
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1631 PhiNode* phi2 = out->as_Phi(); |
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1632 Node *incr2 = phi2->in( LoopNode::LoopBackControl ); |
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1633 // Look for induction variables of the form: X += constant |
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1634 if (phi2->region() != loop->_head || |
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1635 incr2->req() != 3 || |
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1636 incr2->in(1) != phi2 || |
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1637 incr2 == incr || |
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1638 incr2->Opcode() != Op_AddI || |
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1639 !incr2->in(2)->is_Con()) |
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1640 continue; |
|
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|
1641 |
|
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1642 // Check for parallel induction variable (parallel to trip counter) |
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1643 // via an affine function. In particular, count-down loops with |
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1644 // count-up array indices are common. We only RCE references off |
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1645 // the trip-counter, so we need to convert all these to trip-counter |
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1646 // expressions. |
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1647 Node *init2 = phi2->in( LoopNode::EntryControl ); |
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1648 int stride_con2 = incr2->in(2)->get_int(); |
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1649 |
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1650 // The general case here gets a little tricky. We want to find the |
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1651 // GCD of all possible parallel IV's and make a new IV using this |
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1652 // GCD for the loop. Then all possible IVs are simple multiples of |
|
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1653 // the GCD. In practice, this will cover very few extra loops. |
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1654 // Instead we require 'stride_con2' to be a multiple of 'stride_con', |
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1655 // where +/-1 is the common case, but other integer multiples are |
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1656 // also easy to handle. |
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1657 int ratio_con = stride_con2/stride_con; |
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1658 |
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1659 if ((ratio_con * stride_con) == stride_con2) { // Check for exact |
|
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1660 #ifndef PRODUCT |
|
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1661 if (TraceLoopOpts) { |
|
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1662 tty->print("Parallel IV: %d ", phi2->_idx); |
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1663 loop->dump_head(); |
|
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1664 } |
|
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1665 #endif |
|
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1666 // Convert to using the trip counter. The parallel induction |
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1667 // variable differs from the trip counter by a loop-invariant |
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1668 // amount, the difference between their respective initial values. |
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1669 // It is scaled by the 'ratio_con'. |
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1670 Node* ratio = _igvn.intcon(ratio_con); |
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1671 set_ctrl(ratio, C->root()); |
|
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1672 Node* ratio_init = new (C, 3) MulINode(init, ratio); |
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1673 _igvn.register_new_node_with_optimizer(ratio_init, init); |
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1674 set_early_ctrl(ratio_init); |
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1675 Node* diff = new (C, 3) SubINode(init2, ratio_init); |
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1676 _igvn.register_new_node_with_optimizer(diff, init2); |
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1677 set_early_ctrl(diff); |
|
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1678 Node* ratio_idx = new (C, 3) MulINode(phi, ratio); |
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1679 _igvn.register_new_node_with_optimizer(ratio_idx, phi); |
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1680 set_ctrl(ratio_idx, cl); |
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1681 Node* add = new (C, 3) AddINode(ratio_idx, diff); |
|
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1682 _igvn.register_new_node_with_optimizer(add); |
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1683 set_ctrl(add, cl); |
|
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1684 _igvn.replace_node( phi2, add ); |
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1685 // Sometimes an induction variable is unused |
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1686 if (add->outcnt() == 0) { |
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1687 _igvn.remove_dead_node(add); |
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1688 } |
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1689 --i; // deleted this phi; rescan starting with next position |
|
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1690 continue; |
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1691 } |
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1692 } |
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1693 } |
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1694 |
| 0 | 1695 //------------------------------counted_loop----------------------------------- |
| 1696 // Convert to counted loops where possible | |
| 1697 void IdealLoopTree::counted_loop( PhaseIdealLoop *phase ) { | |
| 1698 | |
| 1699 // For grins, set the inner-loop flag here | |
|
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1700 if (!_child) { |
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1701 if (_head->is_Loop()) _head->as_Loop()->set_inner_loop(); |
| 0 | 1702 } |
| 1703 | |
|
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1704 if (_head->is_CountedLoop() || |
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1705 phase->is_counted_loop(_head, this)) { |
| 0 | 1706 _has_sfpt = 1; // Indicate we do not need a safepoint here |
| 1707 | |
| 1708 // Look for a safepoint to remove | |
| 1709 for (Node* n = tail(); n != _head; n = phase->idom(n)) | |
| 1710 if (n->Opcode() == Op_SafePoint && phase->get_loop(n) == this && | |
| 1711 phase->is_deleteable_safept(n)) | |
| 1712 phase->lazy_replace(n,n->in(TypeFunc::Control)); | |
| 1713 | |
| 1714 // Look for induction variables | |
|
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1715 phase->replace_parallel_iv(this); |
| 0 | 1716 |
| 1717 } else if (_parent != NULL && !_irreducible) { | |
| 1718 // Not a counted loop. | |
| 1719 // Look for a safepoint on the idom-path to remove, preserving the first one | |
| 1720 bool found = false; | |
| 1721 Node* n = tail(); | |
| 1722 for (; n != _head && !found; n = phase->idom(n)) { | |
| 1723 if (n->Opcode() == Op_SafePoint && phase->get_loop(n) == this) | |
| 1724 found = true; // Found one | |
| 1725 } | |
| 1726 // Skip past it and delete the others | |
| 1727 for (; n != _head; n = phase->idom(n)) { | |
| 1728 if (n->Opcode() == Op_SafePoint && phase->get_loop(n) == this && | |
| 1729 phase->is_deleteable_safept(n)) | |
| 1730 phase->lazy_replace(n,n->in(TypeFunc::Control)); | |
| 1731 } | |
| 1732 } | |
| 1733 | |
| 1734 // Recursively | |
|
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1735 if (_child) _child->counted_loop( phase ); |
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1736 if (_next) _next ->counted_loop( phase ); |
| 0 | 1737 } |
| 1738 | |
| 1739 #ifndef PRODUCT | |
| 1740 //------------------------------dump_head-------------------------------------- | |
| 1741 // Dump 1 liner for loop header info | |
| 1742 void IdealLoopTree::dump_head( ) const { | |
|
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1743 for (uint i=0; i<_nest; i++) |
| 0 | 1744 tty->print(" "); |
| 1745 tty->print("Loop: N%d/N%d ",_head->_idx,_tail->_idx); | |
|
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1746 if (_irreducible) tty->print(" IRREDUCIBLE"); |
| 3345 | 1747 Node* entry = _head->in(LoopNode::EntryControl); |
| 1748 if (LoopLimitCheck) { | |
| 1749 Node* predicate = PhaseIdealLoop::find_predicate_insertion_point(entry, Deoptimization::Reason_loop_limit_check); | |
| 1750 if (predicate != NULL ) { | |
| 1751 tty->print(" limit_check"); | |
| 1752 entry = entry->in(0)->in(0); | |
| 1753 } | |
| 1754 } | |
|
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1755 if (UseLoopPredicate) { |
| 3345 | 1756 entry = PhaseIdealLoop::find_predicate_insertion_point(entry, Deoptimization::Reason_predicate); |
| 2445 | 1757 if (entry != NULL) { |
|
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1758 tty->print(" predicated"); |
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1759 } |
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1760 } |
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1761 if (_head->is_CountedLoop()) { |
| 0 | 1762 CountedLoopNode *cl = _head->as_CountedLoop(); |
| 1763 tty->print(" counted"); | |
| 2465 | 1764 |
| 1765 Node* init_n = cl->init_trip(); | |
| 1766 if (init_n != NULL && init_n->is_Con()) | |
| 1767 tty->print(" [%d,", cl->init_trip()->get_int()); | |
| 1768 else | |
| 1769 tty->print(" [int,"); | |
| 1770 Node* limit_n = cl->limit(); | |
| 1771 if (limit_n != NULL && limit_n->is_Con()) | |
| 1772 tty->print("%d),", cl->limit()->get_int()); | |
| 1773 else | |
| 1774 tty->print("int),"); | |
| 1775 int stride_con = cl->stride_con(); | |
| 1776 if (stride_con > 0) tty->print("+"); | |
| 1777 tty->print("%d", stride_con); | |
| 1778 | |
|
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1779 if (cl->is_pre_loop ()) tty->print(" pre" ); |
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1780 if (cl->is_main_loop()) tty->print(" main"); |
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1781 if (cl->is_post_loop()) tty->print(" post"); |
| 0 | 1782 } |
| 1783 tty->cr(); | |
| 1784 } | |
| 1785 | |
| 1786 //------------------------------dump------------------------------------------- | |
| 1787 // Dump loops by loop tree | |
| 1788 void IdealLoopTree::dump( ) const { | |
| 1789 dump_head(); | |
|
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1790 if (_child) _child->dump(); |
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1791 if (_next) _next ->dump(); |
| 0 | 1792 } |
| 1793 | |
| 1794 #endif | |
| 1795 | |
|
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1796 static void log_loop_tree(IdealLoopTree* root, IdealLoopTree* loop, CompileLog* log) { |
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1797 if (loop == root) { |
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1798 if (loop->_child != NULL) { |
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1799 log->begin_head("loop_tree"); |
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1800 log->end_head(); |
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1801 if( loop->_child ) log_loop_tree(root, loop->_child, log); |
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1802 log->tail("loop_tree"); |
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1803 assert(loop->_next == NULL, "what?"); |
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1804 } |
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1805 } else { |
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1806 Node* head = loop->_head; |
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1807 log->begin_head("loop"); |
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1808 log->print(" idx='%d' ", head->_idx); |
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1809 if (loop->_irreducible) log->print("irreducible='1' "); |
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1810 if (head->is_Loop()) { |
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1811 if (head->as_Loop()->is_inner_loop()) log->print("inner_loop='1' "); |
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1812 if (head->as_Loop()->is_partial_peel_loop()) log->print("partial_peel_loop='1' "); |
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1813 } |
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1814 if (head->is_CountedLoop()) { |
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1815 CountedLoopNode* cl = head->as_CountedLoop(); |
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1816 if (cl->is_pre_loop()) log->print("pre_loop='%d' ", cl->main_idx()); |
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1817 if (cl->is_main_loop()) log->print("main_loop='%d' ", cl->_idx); |
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1818 if (cl->is_post_loop()) log->print("post_loop='%d' ", cl->main_idx()); |
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1819 } |
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1820 log->end_head(); |
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1821 if( loop->_child ) log_loop_tree(root, loop->_child, log); |
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1822 log->tail("loop"); |
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1823 if( loop->_next ) log_loop_tree(root, loop->_next, log); |
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1824 } |
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1825 } |
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1826 |
| 1172 | 1827 //---------------------collect_potentially_useful_predicates----------------------- |
| 1828 // Helper function to collect potentially useful predicates to prevent them from | |
| 1829 // being eliminated by PhaseIdealLoop::eliminate_useless_predicates | |
| 1830 void PhaseIdealLoop::collect_potentially_useful_predicates( | |
| 1831 IdealLoopTree * loop, Unique_Node_List &useful_predicates) { | |
| 1832 if (loop->_child) { // child | |
| 1833 collect_potentially_useful_predicates(loop->_child, useful_predicates); | |
| 1834 } | |
| 1835 | |
| 1836 // self (only loops that we can apply loop predication may use their predicates) | |
|
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1837 if (loop->_head->is_Loop() && |
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1838 !loop->_irreducible && |
| 1172 | 1839 !loop->tail()->is_top()) { |
|
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1840 LoopNode* lpn = loop->_head->as_Loop(); |
| 1172 | 1841 Node* entry = lpn->in(LoopNode::EntryControl); |
| 3345 | 1842 Node* predicate_proj = find_predicate(entry); // loop_limit_check first |
| 1172 | 1843 if (predicate_proj != NULL ) { // right pattern that can be used by loop predication |
|
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1844 assert(entry->in(0)->in(1)->in(1)->Opcode() == Op_Opaque1, "must be"); |
| 1172 | 1845 useful_predicates.push(entry->in(0)->in(1)->in(1)); // good one |
| 3345 | 1846 entry = entry->in(0)->in(0); |
| 1847 } | |
| 1848 predicate_proj = find_predicate(entry); // Predicate | |
| 1849 if (predicate_proj != NULL ) { | |
| 1850 useful_predicates.push(entry->in(0)->in(1)->in(1)); // good one | |
| 1172 | 1851 } |
| 1852 } | |
| 1853 | |
|
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1854 if (loop->_next) { // sibling |
| 1172 | 1855 collect_potentially_useful_predicates(loop->_next, useful_predicates); |
| 1856 } | |
| 1857 } | |
| 1858 | |
| 1859 //------------------------eliminate_useless_predicates----------------------------- | |
| 1860 // Eliminate all inserted predicates if they could not be used by loop predication. | |
| 3345 | 1861 // Note: it will also eliminates loop limits check predicate since it also uses |
| 1862 // Opaque1 node (see Parse::add_predicate()). | |
| 1172 | 1863 void PhaseIdealLoop::eliminate_useless_predicates() { |
|
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1864 if (C->predicate_count() == 0) |
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1865 return; // no predicate left |
| 1172 | 1866 |
| 1867 Unique_Node_List useful_predicates; // to store useful predicates | |
| 1868 if (C->has_loops()) { | |
| 1869 collect_potentially_useful_predicates(_ltree_root->_child, useful_predicates); | |
| 1870 } | |
| 1871 | |
| 1872 for (int i = C->predicate_count(); i > 0; i--) { | |
| 1873 Node * n = C->predicate_opaque1_node(i-1); | |
| 1874 assert(n->Opcode() == Op_Opaque1, "must be"); | |
| 1875 if (!useful_predicates.member(n)) { // not in the useful list | |
| 1876 _igvn.replace_node(n, n->in(1)); | |
| 1877 } | |
| 1878 } | |
| 1879 } | |
| 1880 | |
| 0 | 1881 //============================================================================= |
|
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1882 //----------------------------build_and_optimize------------------------------- |
| 0 | 1883 // Create a PhaseLoop. Build the ideal Loop tree. Map each Ideal Node to |
| 1884 // its corresponding LoopNode. If 'optimize' is true, do some loop cleanups. | |
|
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1885 void PhaseIdealLoop::build_and_optimize(bool do_split_ifs, bool skip_loop_opts) { |
|
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1886 ResourceMark rm; |
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1887 |
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1888 int old_progress = C->major_progress(); |
| 2403 | 1889 uint orig_worklist_size = _igvn._worklist.size(); |
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1890 |
| 0 | 1891 // Reset major-progress flag for the driver's heuristics |
| 1892 C->clear_major_progress(); | |
| 1893 | |
| 1894 #ifndef PRODUCT | |
| 1895 // Capture for later assert | |
| 1896 uint unique = C->unique(); | |
| 1897 _loop_invokes++; | |
| 1898 _loop_work += unique; | |
| 1899 #endif | |
| 1900 | |
| 1901 // True if the method has at least 1 irreducible loop | |
| 1902 _has_irreducible_loops = false; | |
| 1903 | |
| 1904 _created_loop_node = false; | |
| 1905 | |
| 1906 Arena *a = Thread::current()->resource_area(); | |
| 1907 VectorSet visited(a); | |
| 1908 // Pre-grow the mapping from Nodes to IdealLoopTrees. | |
| 1909 _nodes.map(C->unique(), NULL); | |
| 1910 memset(_nodes.adr(), 0, wordSize * C->unique()); | |
| 1911 | |
| 1912 // Pre-build the top-level outermost loop tree entry | |
| 1913 _ltree_root = new IdealLoopTree( this, C->root(), C->root() ); | |
| 1914 // Do not need a safepoint at the top level | |
| 1915 _ltree_root->_has_sfpt = 1; | |
| 1916 | |
| 2445 | 1917 // Initialize Dominators. |
| 1918 // Checked in clone_loop_predicate() during beautify_loops(). | |
| 1919 _idom_size = 0; | |
| 1920 _idom = NULL; | |
| 1921 _dom_depth = NULL; | |
| 1922 _dom_stk = NULL; | |
| 1923 | |
| 0 | 1924 // Empty pre-order array |
| 1925 allocate_preorders(); | |
| 1926 | |
| 1927 // Build a loop tree on the fly. Build a mapping from CFG nodes to | |
| 1928 // IdealLoopTree entries. Data nodes are NOT walked. | |
| 1929 build_loop_tree(); | |
| 1930 // Check for bailout, and return | |
| 1931 if (C->failing()) { | |
| 1932 return; | |
| 1933 } | |
| 1934 | |
| 1935 // No loops after all | |
|
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1936 if( !_ltree_root->_child && !_verify_only ) C->set_has_loops(false); |
| 0 | 1937 |
| 1938 // There should always be an outer loop containing the Root and Return nodes. | |
| 1939 // If not, we have a degenerate empty program. Bail out in this case. | |
| 1940 if (!has_node(C->root())) { | |
|
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1941 if (!_verify_only) { |
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1942 C->clear_major_progress(); |
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1943 C->record_method_not_compilable("empty program detected during loop optimization"); |
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1944 } |
| 0 | 1945 return; |
| 1946 } | |
| 1947 | |
| 1948 // Nothing to do, so get out | |
|
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1949 if( !C->has_loops() && !do_split_ifs && !_verify_me && !_verify_only ) { |
| 0 | 1950 _igvn.optimize(); // Cleanup NeverBranches |
| 1951 return; | |
| 1952 } | |
| 1953 | |
| 1954 // Set loop nesting depth | |
| 1955 _ltree_root->set_nest( 0 ); | |
| 1956 | |
| 1957 // Split shared headers and insert loop landing pads. | |
| 1958 // Do not bother doing this on the Root loop of course. | |
|
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1959 if( !_verify_me && !_verify_only && _ltree_root->_child ) { |
| 2403 | 1960 C->print_method("Before beautify loops", 3); |
| 0 | 1961 if( _ltree_root->_child->beautify_loops( this ) ) { |
| 1962 // Re-build loop tree! | |
| 1963 _ltree_root->_child = NULL; | |
| 1964 _nodes.clear(); | |
| 1965 reallocate_preorders(); | |
| 1966 build_loop_tree(); | |
| 1967 // Check for bailout, and return | |
| 1968 if (C->failing()) { | |
| 1969 return; | |
| 1970 } | |
| 1971 // Reset loop nesting depth | |
| 1972 _ltree_root->set_nest( 0 ); | |
| 222 | 1973 |
| 1974 C->print_method("After beautify loops", 3); | |
| 0 | 1975 } |
| 1976 } | |
| 1977 | |
| 1978 // Build Dominators for elision of NULL checks & loop finding. | |
| 1979 // Since nodes do not have a slot for immediate dominator, make | |
| 605 | 1980 // a persistent side array for that info indexed on node->_idx. |
| 0 | 1981 _idom_size = C->unique(); |
| 1982 _idom = NEW_RESOURCE_ARRAY( Node*, _idom_size ); | |
| 1983 _dom_depth = NEW_RESOURCE_ARRAY( uint, _idom_size ); | |
| 1984 _dom_stk = NULL; // Allocated on demand in recompute_dom_depth | |
| 1985 memset( _dom_depth, 0, _idom_size * sizeof(uint) ); | |
| 1986 | |
| 1987 Dominators(); | |
| 1988 | |
|
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1989 if (!_verify_only) { |
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1990 // As a side effect, Dominators removed any unreachable CFG paths |
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1991 // into RegionNodes. It doesn't do this test against Root, so |
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1992 // we do it here. |
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1993 for( uint i = 1; i < C->root()->req(); i++ ) { |
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1994 if( !_nodes[C->root()->in(i)->_idx] ) { // Dead path into Root? |
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1995 _igvn.hash_delete(C->root()); |
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1996 C->root()->del_req(i); |
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1997 _igvn._worklist.push(C->root()); |
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1998 i--; // Rerun same iteration on compressed edges |
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1999 } |
| 0 | 2000 } |
|
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2001 |
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2002 // Given dominators, try to find inner loops with calls that must |
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2003 // always be executed (call dominates loop tail). These loops do |
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2004 // not need a separate safepoint. |
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2005 Node_List cisstack(a); |
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2006 _ltree_root->check_safepts(visited, cisstack); |
| 0 | 2007 } |
| 2008 | |
| 2009 // Walk the DATA nodes and place into loops. Find earliest control | |
| 2010 // node. For CFG nodes, the _nodes array starts out and remains | |
| 2011 // holding the associated IdealLoopTree pointer. For DATA nodes, the | |
| 2012 // _nodes array holds the earliest legal controlling CFG node. | |
| 2013 | |
| 2014 // Allocate stack with enough space to avoid frequent realloc | |
| 2015 int stack_size = (C->unique() >> 1) + 16; // (unique>>1)+16 from Java2D stats | |
| 2016 Node_Stack nstack( a, stack_size ); | |
| 2017 | |
| 2018 visited.Clear(); | |
| 2019 Node_List worklist(a); | |
| 2020 // Don't need C->root() on worklist since | |
| 2021 // it will be processed among C->top() inputs | |
| 2022 worklist.push( C->top() ); | |
| 2023 visited.set( C->top()->_idx ); // Set C->top() as visited now | |
|
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2024 build_loop_early( visited, worklist, nstack ); |
| 0 | 2025 |
| 2026 // Given early legal placement, try finding counted loops. This placement | |
| 2027 // is good enough to discover most loop invariants. | |
|
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2028 if( !_verify_me && !_verify_only ) |
| 0 | 2029 _ltree_root->counted_loop( this ); |
| 2030 | |
| 2031 // Find latest loop placement. Find ideal loop placement. | |
| 2032 visited.Clear(); | |
| 2033 init_dom_lca_tags(); | |
| 2034 // Need C->root() on worklist when processing outs | |
| 2035 worklist.push( C->root() ); | |
| 2036 NOT_PRODUCT( C->verify_graph_edges(); ) | |
| 2037 worklist.push( C->top() ); | |
|
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2038 build_loop_late( visited, worklist, nstack ); |
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2039 |
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2040 if (_verify_only) { |
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2041 // restore major progress flag |
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2042 for (int i = 0; i < old_progress; i++) |
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2043 C->set_major_progress(); |
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2044 assert(C->unique() == unique, "verification mode made Nodes? ? ?"); |
| 2403 | 2045 assert(_igvn._worklist.size() == orig_worklist_size, "shouldn't push anything"); |
|
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2046 return; |
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2047 } |
| 0 | 2048 |
| 2445 | 2049 // Some parser-inserted loop predicates could never be used by loop |
| 2050 // predication or they were moved away from loop during some optimizations. | |
| 2051 // For example, peeling. Eliminate them before next loop optimizations. | |
| 3345 | 2052 if (UseLoopPredicate || LoopLimitCheck) { |
| 1172 | 2053 eliminate_useless_predicates(); |
| 2054 } | |
| 2055 | |
| 0 | 2056 // clear out the dead code |
| 2057 while(_deadlist.size()) { | |
|
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2058 _igvn.remove_globally_dead_node(_deadlist.pop()); |
| 0 | 2059 } |
| 2060 | |
| 2061 #ifndef PRODUCT | |
| 2062 C->verify_graph_edges(); | |
|
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2063 if (_verify_me) { // Nested verify pass? |
| 0 | 2064 // Check to see if the verify mode is broken |
| 2065 assert(C->unique() == unique, "non-optimize mode made Nodes? ? ?"); | |
| 2066 return; | |
| 2067 } | |
|
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2068 if(VerifyLoopOptimizations) verify(); |
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2069 if(TraceLoopOpts && C->has_loops()) { |
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2070 _ltree_root->dump(); |
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2071 } |
| 0 | 2072 #endif |
| 2073 | |
|
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2074 if (skip_loop_opts) { |
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2075 // Cleanup any modified bits |
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2076 _igvn.optimize(); |
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2077 |
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2078 if (C->log() != NULL) { |
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2079 log_loop_tree(_ltree_root, _ltree_root, C->log()); |
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2080 } |
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2081 return; |
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2082 } |
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2083 |
| 0 | 2084 if (ReassociateInvariants) { |
| 2085 // Reassociate invariants and prep for split_thru_phi | |
| 2086 for (LoopTreeIterator iter(_ltree_root); !iter.done(); iter.next()) { | |
| 2087 IdealLoopTree* lpt = iter.current(); | |
| 2088 if (!lpt->is_counted() || !lpt->is_inner()) continue; | |
| 2089 | |
| 2090 lpt->reassociate_invariants(this); | |
| 2091 | |
| 2092 // Because RCE opportunities can be masked by split_thru_phi, | |
| 2093 // look for RCE candidates and inhibit split_thru_phi | |
| 2094 // on just their loop-phi's for this pass of loop opts | |
| 1172 | 2095 if (SplitIfBlocks && do_split_ifs) { |
| 0 | 2096 if (lpt->policy_range_check(this)) { |
|
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2097 lpt->_rce_candidate = 1; // = true |
| 0 | 2098 } |
| 2099 } | |
| 2100 } | |
| 2101 } | |
| 2102 | |
| 2103 // Check for aggressive application of split-if and other transforms | |
| 2104 // that require basic-block info (like cloning through Phi's) | |
| 2105 if( SplitIfBlocks && do_split_ifs ) { | |
| 2106 visited.Clear(); | |
| 2107 split_if_with_blocks( visited, nstack ); | |
| 2108 NOT_PRODUCT( if( VerifyLoopOptimizations ) verify(); ); | |
| 2109 } | |
| 2110 | |
| 1172 | 2111 // Perform loop predication before iteration splitting |
| 2445 | 2112 if (C->has_loops() && !C->major_progress() && (C->predicate_count() > 0)) { |
| 1172 | 2113 _ltree_root->_child->loop_predication(this); |
| 2114 } | |
| 2115 | |
| 1763 | 2116 if (OptimizeFill && UseLoopPredicate && C->has_loops() && !C->major_progress()) { |
| 2117 if (do_intrinsify_fill()) { | |
| 2118 C->set_major_progress(); | |
| 2119 } | |
| 2120 } | |
| 2121 | |
| 0 | 2122 // Perform iteration-splitting on inner loops. Split iterations to avoid |
| 2123 // range checks or one-shot null checks. | |
| 2124 | |
| 2125 // If split-if's didn't hack the graph too bad (no CFG changes) | |
| 2126 // then do loop opts. | |
| 1172 | 2127 if (C->has_loops() && !C->major_progress()) { |
| 0 | 2128 memset( worklist.adr(), 0, worklist.Size()*sizeof(Node*) ); |
| 2129 _ltree_root->_child->iteration_split( this, worklist ); | |
| 2130 // No verify after peeling! GCM has hoisted code out of the loop. | |
| 2131 // After peeling, the hoisted code could sink inside the peeled area. | |
| 2132 // The peeling code does not try to recompute the best location for | |
| 2133 // all the code before the peeled area, so the verify pass will always | |
| 2134 // complain about it. | |
| 2135 } | |
| 2136 // Do verify graph edges in any case | |
| 2137 NOT_PRODUCT( C->verify_graph_edges(); ); | |
| 2138 | |
| 1172 | 2139 if (!do_split_ifs) { |
| 0 | 2140 // We saw major progress in Split-If to get here. We forced a |
| 2141 // pass with unrolling and not split-if, however more split-if's | |
| 2142 // might make progress. If the unrolling didn't make progress | |
| 2143 // then the major-progress flag got cleared and we won't try | |
| 2144 // another round of Split-If. In particular the ever-common | |
| 2145 // instance-of/check-cast pattern requires at least 2 rounds of | |
| 2146 // Split-If to clear out. | |
| 2147 C->set_major_progress(); | |
| 2148 } | |
| 2149 | |
| 2150 // Repeat loop optimizations if new loops were seen | |
| 2151 if (created_loop_node()) { | |
| 2152 C->set_major_progress(); | |
| 2153 } | |
| 2154 | |
| 2445 | 2155 // Keep loop predicates and perform optimizations with them |
| 2156 // until no more loop optimizations could be done. | |
| 2157 // After that switch predicates off and do more loop optimizations. | |
| 2158 if (!C->major_progress() && (C->predicate_count() > 0)) { | |
| 2159 C->cleanup_loop_predicates(_igvn); | |
| 2160 #ifndef PRODUCT | |
| 2161 if (TraceLoopOpts) { | |
| 2162 tty->print_cr("PredicatesOff"); | |
| 2163 } | |
| 2164 #endif | |
| 2165 C->set_major_progress(); | |
| 2166 } | |
| 0 | 2167 |
| 2445 | 2168 // Convert scalar to superword operations at the end of all loop opts. |
| 0 | 2169 if (UseSuperWord && C->has_loops() && !C->major_progress()) { |
| 2170 // SuperWord transform | |
| 2171 SuperWord sw(this); | |
| 2172 for (LoopTreeIterator iter(_ltree_root); !iter.done(); iter.next()) { | |
| 2173 IdealLoopTree* lpt = iter.current(); | |
| 2174 if (lpt->is_counted()) { | |
| 2175 sw.transform_loop(lpt); | |
| 2176 } | |
| 2177 } | |
| 2178 } | |
| 2179 | |
| 2180 // Cleanup any modified bits | |
| 2181 _igvn.optimize(); | |
| 2182 | |
|
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2183 // disable assert until issue with split_flow_path is resolved (6742111) |
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2184 // assert(!_has_irreducible_loops || C->parsed_irreducible_loop() || C->is_osr_compilation(), |
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2185 // "shouldn't introduce irreducible loops"); |
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2186 |
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2187 if (C->log() != NULL) { |
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2188 log_loop_tree(_ltree_root, _ltree_root, C->log()); |
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2189 } |
| 0 | 2190 } |
| 2191 | |
| 2192 #ifndef PRODUCT | |
| 2193 //------------------------------print_statistics------------------------------- | |
| 2194 int PhaseIdealLoop::_loop_invokes=0;// Count of PhaseIdealLoop invokes | |
| 2195 int PhaseIdealLoop::_loop_work=0; // Sum of PhaseIdealLoop x unique | |
| 2196 void PhaseIdealLoop::print_statistics() { | |
| 2197 tty->print_cr("PhaseIdealLoop=%d, sum _unique=%d", _loop_invokes, _loop_work); | |
| 2198 } | |
| 2199 | |
| 2200 //------------------------------verify----------------------------------------- | |
| 2201 // Build a verify-only PhaseIdealLoop, and see that it agrees with me. | |
| 2202 static int fail; // debug only, so its multi-thread dont care | |
| 2203 void PhaseIdealLoop::verify() const { | |
| 2204 int old_progress = C->major_progress(); | |
| 2205 ResourceMark rm; | |
|
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2206 PhaseIdealLoop loop_verify( _igvn, this ); |
| 0 | 2207 VectorSet visited(Thread::current()->resource_area()); |
| 2208 | |
| 2209 fail = 0; | |
| 2210 verify_compare( C->root(), &loop_verify, visited ); | |
| 2211 assert( fail == 0, "verify loops failed" ); | |
| 2212 // Verify loop structure is the same | |
| 2213 _ltree_root->verify_tree(loop_verify._ltree_root, NULL); | |
| 2214 // Reset major-progress. It was cleared by creating a verify version of | |
| 2215 // PhaseIdealLoop. | |
| 2216 for( int i=0; i<old_progress; i++ ) | |
| 2217 C->set_major_progress(); | |
| 2218 } | |
| 2219 | |
| 2220 //------------------------------verify_compare--------------------------------- | |
| 2221 // Make sure me and the given PhaseIdealLoop agree on key data structures | |
| 2222 void PhaseIdealLoop::verify_compare( Node *n, const PhaseIdealLoop *loop_verify, VectorSet &visited ) const { | |
| 2223 if( !n ) return; | |
| 2224 if( visited.test_set( n->_idx ) ) return; | |
| 2225 if( !_nodes[n->_idx] ) { // Unreachable | |
| 2226 assert( !loop_verify->_nodes[n->_idx], "both should be unreachable" ); | |
| 2227 return; | |
| 2228 } | |
| 2229 | |
| 2230 uint i; | |
| 2231 for( i = 0; i < n->req(); i++ ) | |
| 2232 verify_compare( n->in(i), loop_verify, visited ); | |
| 2233 | |
| 2234 // Check the '_nodes' block/loop structure | |
| 2235 i = n->_idx; | |
| 2236 if( has_ctrl(n) ) { // We have control; verify has loop or ctrl | |
| 2237 if( _nodes[i] != loop_verify->_nodes[i] && | |
| 2238 get_ctrl_no_update(n) != loop_verify->get_ctrl_no_update(n) ) { | |
| 2239 tty->print("Mismatched control setting for: "); | |
| 2240 n->dump(); | |
| 2241 if( fail++ > 10 ) return; | |
| 2242 Node *c = get_ctrl_no_update(n); | |
| 2243 tty->print("We have it as: "); | |
| 2244 if( c->in(0) ) c->dump(); | |
| 2245 else tty->print_cr("N%d",c->_idx); | |
| 2246 tty->print("Verify thinks: "); | |
| 2247 if( loop_verify->has_ctrl(n) ) | |
| 2248 loop_verify->get_ctrl_no_update(n)->dump(); | |
| 2249 else | |
| 2250 loop_verify->get_loop_idx(n)->dump(); | |
| 2251 tty->cr(); | |
| 2252 } | |
| 2253 } else { // We have a loop | |
| 2254 IdealLoopTree *us = get_loop_idx(n); | |
| 2255 if( loop_verify->has_ctrl(n) ) { | |
| 2256 tty->print("Mismatched loop setting for: "); | |
| 2257 n->dump(); | |
| 2258 if( fail++ > 10 ) return; | |
| 2259 tty->print("We have it as: "); | |
| 2260 us->dump(); | |
| 2261 tty->print("Verify thinks: "); | |
| 2262 loop_verify->get_ctrl_no_update(n)->dump(); | |
| 2263 tty->cr(); | |
| 2264 } else if (!C->major_progress()) { | |
| 2265 // Loop selection can be messed up if we did a major progress | |
| 2266 // operation, like split-if. Do not verify in that case. | |
| 2267 IdealLoopTree *them = loop_verify->get_loop_idx(n); | |
| 2268 if( us->_head != them->_head || us->_tail != them->_tail ) { | |
| 2269 tty->print("Unequals loops for: "); | |
| 2270 n->dump(); | |
| 2271 if( fail++ > 10 ) return; | |
| 2272 tty->print("We have it as: "); | |
| 2273 us->dump(); | |
| 2274 tty->print("Verify thinks: "); | |
| 2275 them->dump(); | |
| 2276 tty->cr(); | |
| 2277 } | |
| 2278 } | |
| 2279 } | |
| 2280 | |
| 2281 // Check for immediate dominators being equal | |
| 2282 if( i >= _idom_size ) { | |
| 2283 if( !n->is_CFG() ) return; | |
| 2284 tty->print("CFG Node with no idom: "); | |
| 2285 n->dump(); | |
| 2286 return; | |
| 2287 } | |
| 2288 if( !n->is_CFG() ) return; | |
| 2289 if( n == C->root() ) return; // No IDOM here | |
| 2290 | |
| 2291 assert(n->_idx == i, "sanity"); | |
| 2292 Node *id = idom_no_update(n); | |
| 2293 if( id != loop_verify->idom_no_update(n) ) { | |
| 2294 tty->print("Unequals idoms for: "); | |
| 2295 n->dump(); | |
| 2296 if( fail++ > 10 ) return; | |
| 2297 tty->print("We have it as: "); | |
| 2298 id->dump(); | |
| 2299 tty->print("Verify thinks: "); | |
| 2300 loop_verify->idom_no_update(n)->dump(); | |
| 2301 tty->cr(); | |
| 2302 } | |
| 2303 | |
| 2304 } | |
| 2305 | |
| 2306 //------------------------------verify_tree------------------------------------ | |
| 2307 // Verify that tree structures match. Because the CFG can change, siblings | |
| 2308 // within the loop tree can be reordered. We attempt to deal with that by | |
| 2309 // reordering the verify's loop tree if possible. | |
| 2310 void IdealLoopTree::verify_tree(IdealLoopTree *loop, const IdealLoopTree *parent) const { | |
| 2311 assert( _parent == parent, "Badly formed loop tree" ); | |
| 2312 | |
| 2313 // Siblings not in same order? Attempt to re-order. | |
| 2314 if( _head != loop->_head ) { | |
| 2315 // Find _next pointer to update | |
| 2316 IdealLoopTree **pp = &loop->_parent->_child; | |
| 2317 while( *pp != loop ) | |
| 2318 pp = &((*pp)->_next); | |
| 2319 // Find proper sibling to be next | |
| 2320 IdealLoopTree **nn = &loop->_next; | |
| 2321 while( (*nn) && (*nn)->_head != _head ) | |
| 2322 nn = &((*nn)->_next); | |
| 2323 | |
| 2324 // Check for no match. | |
| 2325 if( !(*nn) ) { | |
| 2326 // Annoyingly, irreducible loops can pick different headers | |
| 2327 // after a major_progress operation, so the rest of the loop | |
| 2328 // tree cannot be matched. | |
| 2329 if (_irreducible && Compile::current()->major_progress()) return; | |
| 2330 assert( 0, "failed to match loop tree" ); | |
| 2331 } | |
| 2332 | |
| 2333 // Move (*nn) to (*pp) | |
| 2334 IdealLoopTree *hit = *nn; | |
| 2335 *nn = hit->_next; | |
| 2336 hit->_next = loop; | |
| 2337 *pp = loop; | |
| 2338 loop = hit; | |
| 2339 // Now try again to verify | |
| 2340 } | |
| 2341 | |
| 2342 assert( _head == loop->_head , "mismatched loop head" ); | |
| 2343 Node *tail = _tail; // Inline a non-updating version of | |
| 2344 while( !tail->in(0) ) // the 'tail()' call. | |
| 2345 tail = tail->in(1); | |
| 2346 assert( tail == loop->_tail, "mismatched loop tail" ); | |
| 2347 | |
| 2348 // Counted loops that are guarded should be able to find their guards | |
| 2349 if( _head->is_CountedLoop() && _head->as_CountedLoop()->is_main_loop() ) { | |
| 2350 CountedLoopNode *cl = _head->as_CountedLoop(); | |
| 2351 Node *init = cl->init_trip(); | |
| 2352 Node *ctrl = cl->in(LoopNode::EntryControl); | |
| 2353 assert( ctrl->Opcode() == Op_IfTrue || ctrl->Opcode() == Op_IfFalse, "" ); | |
| 2354 Node *iff = ctrl->in(0); | |
| 2355 assert( iff->Opcode() == Op_If, "" ); | |
| 2356 Node *bol = iff->in(1); | |
| 2357 assert( bol->Opcode() == Op_Bool, "" ); | |
| 2358 Node *cmp = bol->in(1); | |
| 2359 assert( cmp->Opcode() == Op_CmpI, "" ); | |
| 2360 Node *add = cmp->in(1); | |
| 2361 Node *opaq; | |
| 2362 if( add->Opcode() == Op_Opaque1 ) { | |
| 2363 opaq = add; | |
| 2364 } else { | |
| 2365 assert( add->Opcode() == Op_AddI || add->Opcode() == Op_ConI , "" ); | |
| 2366 assert( add == init, "" ); | |
| 2367 opaq = cmp->in(2); | |
| 2368 } | |
| 2369 assert( opaq->Opcode() == Op_Opaque1, "" ); | |
| 2370 | |
| 2371 } | |
| 2372 | |
| 2373 if (_child != NULL) _child->verify_tree(loop->_child, this); | |
| 2374 if (_next != NULL) _next ->verify_tree(loop->_next, parent); | |
| 2375 // Innermost loops need to verify loop bodies, | |
| 2376 // but only if no 'major_progress' | |
| 2377 int fail = 0; | |
| 2378 if (!Compile::current()->major_progress() && _child == NULL) { | |
| 2379 for( uint i = 0; i < _body.size(); i++ ) { | |
| 2380 Node *n = _body.at(i); | |
| 2381 if (n->outcnt() == 0) continue; // Ignore dead | |
| 2382 uint j; | |
| 2383 for( j = 0; j < loop->_body.size(); j++ ) | |
| 2384 if( loop->_body.at(j) == n ) | |
| 2385 break; | |
| 2386 if( j == loop->_body.size() ) { // Not found in loop body | |
| 2387 // Last ditch effort to avoid assertion: Its possible that we | |
| 2388 // have some users (so outcnt not zero) but are still dead. | |
| 2389 // Try to find from root. | |
| 2390 if (Compile::current()->root()->find(n->_idx)) { | |
| 2391 fail++; | |
| 2392 tty->print("We have that verify does not: "); | |
| 2393 n->dump(); | |
| 2394 } | |
| 2395 } | |
| 2396 } | |
| 2397 for( uint i2 = 0; i2 < loop->_body.size(); i2++ ) { | |
| 2398 Node *n = loop->_body.at(i2); | |
| 2399 if (n->outcnt() == 0) continue; // Ignore dead | |
| 2400 uint j; | |
| 2401 for( j = 0; j < _body.size(); j++ ) | |
| 2402 if( _body.at(j) == n ) | |
| 2403 break; | |
| 2404 if( j == _body.size() ) { // Not found in loop body | |
| 2405 // Last ditch effort to avoid assertion: Its possible that we | |
| 2406 // have some users (so outcnt not zero) but are still dead. | |
| 2407 // Try to find from root. | |
| 2408 if (Compile::current()->root()->find(n->_idx)) { | |
| 2409 fail++; | |
| 2410 tty->print("Verify has that we do not: "); | |
| 2411 n->dump(); | |
| 2412 } | |
| 2413 } | |
| 2414 } | |
| 2415 assert( !fail, "loop body mismatch" ); | |
| 2416 } | |
| 2417 } | |
| 2418 | |
| 2419 #endif | |
| 2420 | |
| 2421 //------------------------------set_idom--------------------------------------- | |
| 2422 void PhaseIdealLoop::set_idom(Node* d, Node* n, uint dom_depth) { | |
| 2423 uint idx = d->_idx; | |
| 2424 if (idx >= _idom_size) { | |
| 2425 uint newsize = _idom_size<<1; | |
| 2426 while( idx >= newsize ) { | |
| 2427 newsize <<= 1; | |
| 2428 } | |
| 2429 _idom = REALLOC_RESOURCE_ARRAY( Node*, _idom,_idom_size,newsize); | |
| 2430 _dom_depth = REALLOC_RESOURCE_ARRAY( uint, _dom_depth,_idom_size,newsize); | |
| 2431 memset( _dom_depth + _idom_size, 0, (newsize - _idom_size) * sizeof(uint) ); | |
| 2432 _idom_size = newsize; | |
| 2433 } | |
| 2434 _idom[idx] = n; | |
| 2435 _dom_depth[idx] = dom_depth; | |
| 2436 } | |
| 2437 | |
| 2438 //------------------------------recompute_dom_depth--------------------------------------- | |
| 2439 // The dominator tree is constructed with only parent pointers. | |
| 2440 // This recomputes the depth in the tree by first tagging all | |
| 2441 // nodes as "no depth yet" marker. The next pass then runs up | |
| 2442 // the dom tree from each node marked "no depth yet", and computes | |
| 2443 // the depth on the way back down. | |
| 2444 void PhaseIdealLoop::recompute_dom_depth() { | |
| 2445 uint no_depth_marker = C->unique(); | |
| 2446 uint i; | |
| 2447 // Initialize depth to "no depth yet" | |
| 2448 for (i = 0; i < _idom_size; i++) { | |
| 2449 if (_dom_depth[i] > 0 && _idom[i] != NULL) { | |
| 2450 _dom_depth[i] = no_depth_marker; | |
| 2451 } | |
| 2452 } | |
| 2453 if (_dom_stk == NULL) { | |
| 2454 uint init_size = C->unique() / 100; // Guess that 1/100 is a reasonable initial size. | |
| 2455 if (init_size < 10) init_size = 10; | |
|
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2456 _dom_stk = new GrowableArray<uint>(init_size); |
| 0 | 2457 } |
| 2458 // Compute new depth for each node. | |
| 2459 for (i = 0; i < _idom_size; i++) { | |
| 2460 uint j = i; | |
| 2461 // Run up the dom tree to find a node with a depth | |
| 2462 while (_dom_depth[j] == no_depth_marker) { | |
| 2463 _dom_stk->push(j); | |
| 2464 j = _idom[j]->_idx; | |
| 2465 } | |
| 2466 // Compute the depth on the way back down this tree branch | |
| 2467 uint dd = _dom_depth[j] + 1; | |
| 2468 while (_dom_stk->length() > 0) { | |
| 2469 uint j = _dom_stk->pop(); | |
| 2470 _dom_depth[j] = dd; | |
| 2471 dd++; | |
| 2472 } | |
| 2473 } | |
| 2474 } | |
| 2475 | |
| 2476 //------------------------------sort------------------------------------------- | |
| 2477 // Insert 'loop' into the existing loop tree. 'innermost' is a leaf of the | |
| 2478 // loop tree, not the root. | |
| 2479 IdealLoopTree *PhaseIdealLoop::sort( IdealLoopTree *loop, IdealLoopTree *innermost ) { | |
| 2480 if( !innermost ) return loop; // New innermost loop | |
| 2481 | |
| 2482 int loop_preorder = get_preorder(loop->_head); // Cache pre-order number | |
| 2483 assert( loop_preorder, "not yet post-walked loop" ); | |
| 2484 IdealLoopTree **pp = &innermost; // Pointer to previous next-pointer | |
| 2485 IdealLoopTree *l = *pp; // Do I go before or after 'l'? | |
| 2486 | |
| 2487 // Insert at start of list | |
| 2488 while( l ) { // Insertion sort based on pre-order | |
| 2489 if( l == loop ) return innermost; // Already on list! | |
| 2490 int l_preorder = get_preorder(l->_head); // Cache pre-order number | |
| 2491 assert( l_preorder, "not yet post-walked l" ); | |
| 2492 // Check header pre-order number to figure proper nesting | |
| 2493 if( loop_preorder > l_preorder ) | |
| 2494 break; // End of insertion | |
| 2495 // If headers tie (e.g., shared headers) check tail pre-order numbers. | |
| 2496 // Since I split shared headers, you'd think this could not happen. | |
| 2497 // BUT: I must first do the preorder numbering before I can discover I | |
| 2498 // have shared headers, so the split headers all get the same preorder | |
| 2499 // number as the RegionNode they split from. | |
| 2500 if( loop_preorder == l_preorder && | |
| 2501 get_preorder(loop->_tail) < get_preorder(l->_tail) ) | |
| 2502 break; // Also check for shared headers (same pre#) | |
| 2503 pp = &l->_parent; // Chain up list | |
| 2504 l = *pp; | |
| 2505 } | |
| 2506 // Link into list | |
| 2507 // Point predecessor to me | |
| 2508 *pp = loop; | |
| 2509 // Point me to successor | |
| 2510 IdealLoopTree *p = loop->_parent; | |
| 2511 loop->_parent = l; // Point me to successor | |
| 2512 if( p ) sort( p, innermost ); // Insert my parents into list as well | |
| 2513 return innermost; | |
| 2514 } | |
| 2515 | |
| 2516 //------------------------------build_loop_tree-------------------------------- | |
| 2517 // I use a modified Vick/Tarjan algorithm. I need pre- and a post- visit | |
| 2518 // bits. The _nodes[] array is mapped by Node index and holds a NULL for | |
| 2519 // not-yet-pre-walked, pre-order # for pre-but-not-post-walked and holds the | |
| 2520 // tightest enclosing IdealLoopTree for post-walked. | |
| 2521 // | |
| 2522 // During my forward walk I do a short 1-layer lookahead to see if I can find | |
| 2523 // a loop backedge with that doesn't have any work on the backedge. This | |
| 2524 // helps me construct nested loops with shared headers better. | |
| 2525 // | |
| 2526 // Once I've done the forward recursion, I do the post-work. For each child | |
| 2527 // I check to see if there is a backedge. Backedges define a loop! I | |
| 2528 // insert an IdealLoopTree at the target of the backedge. | |
| 2529 // | |
| 2530 // During the post-work I also check to see if I have several children | |
| 2531 // belonging to different loops. If so, then this Node is a decision point | |
| 2532 // where control flow can choose to change loop nests. It is at this | |
| 2533 // decision point where I can figure out how loops are nested. At this | |
| 2534 // time I can properly order the different loop nests from my children. | |
| 2535 // Note that there may not be any backedges at the decision point! | |
| 2536 // | |
| 2537 // Since the decision point can be far removed from the backedges, I can't | |
| 2538 // order my loops at the time I discover them. Thus at the decision point | |
| 2539 // I need to inspect loop header pre-order numbers to properly nest my | |
| 2540 // loops. This means I need to sort my childrens' loops by pre-order. | |
| 2541 // The sort is of size number-of-control-children, which generally limits | |
| 2542 // it to size 2 (i.e., I just choose between my 2 target loops). | |
| 2543 void PhaseIdealLoop::build_loop_tree() { | |
| 2544 // Allocate stack of size C->unique()/2 to avoid frequent realloc | |
| 2545 GrowableArray <Node *> bltstack(C->unique() >> 1); | |
| 2546 Node *n = C->root(); | |
| 2547 bltstack.push(n); | |
| 2548 int pre_order = 1; | |
| 2549 int stack_size; | |
| 2550 | |
| 2551 while ( ( stack_size = bltstack.length() ) != 0 ) { | |
| 2552 n = bltstack.top(); // Leave node on stack | |
| 2553 if ( !is_visited(n) ) { | |
| 2554 // ---- Pre-pass Work ---- | |
| 2555 // Pre-walked but not post-walked nodes need a pre_order number. | |
| 2556 | |
| 2557 set_preorder_visited( n, pre_order ); // set as visited | |
| 2558 | |
| 2559 // ---- Scan over children ---- | |
| 2560 // Scan first over control projections that lead to loop headers. | |
| 2561 // This helps us find inner-to-outer loops with shared headers better. | |
| 2562 | |
| 2563 // Scan children's children for loop headers. | |
| 2564 for ( int i = n->outcnt() - 1; i >= 0; --i ) { | |
| 2565 Node* m = n->raw_out(i); // Child | |
| 2566 if( m->is_CFG() && !is_visited(m) ) { // Only for CFG children | |
| 2567 // Scan over children's children to find loop | |
| 2568 for (DUIterator_Fast jmax, j = m->fast_outs(jmax); j < jmax; j++) { | |
| 2569 Node* l = m->fast_out(j); | |
| 2570 if( is_visited(l) && // Been visited? | |
| 2571 !is_postvisited(l) && // But not post-visited | |
| 2572 get_preorder(l) < pre_order ) { // And smaller pre-order | |
| 2573 // Found! Scan the DFS down this path before doing other paths | |
| 2574 bltstack.push(m); | |
| 2575 break; | |
| 2576 } | |
| 2577 } | |
| 2578 } | |
| 2579 } | |
| 2580 pre_order++; | |
| 2581 } | |
| 2582 else if ( !is_postvisited(n) ) { | |
| 2583 // Note: build_loop_tree_impl() adds out edges on rare occasions, | |
| 2584 // such as com.sun.rsasign.am::a. | |
| 2585 // For non-recursive version, first, process current children. | |
| 2586 // On next iteration, check if additional children were added. | |
| 2587 for ( int k = n->outcnt() - 1; k >= 0; --k ) { | |
| 2588 Node* u = n->raw_out(k); | |
| 2589 if ( u->is_CFG() && !is_visited(u) ) { | |
| 2590 bltstack.push(u); | |
| 2591 } | |
| 2592 } | |
| 2593 if ( bltstack.length() == stack_size ) { | |
| 2594 // There were no additional children, post visit node now | |
| 2595 (void)bltstack.pop(); // Remove node from stack | |
| 2596 pre_order = build_loop_tree_impl( n, pre_order ); | |
| 2597 // Check for bailout | |
| 2598 if (C->failing()) { | |
| 2599 return; | |
| 2600 } | |
| 2601 // Check to grow _preorders[] array for the case when | |
| 2602 // build_loop_tree_impl() adds new nodes. | |
| 2603 check_grow_preorders(); | |
| 2604 } | |
| 2605 } | |
| 2606 else { | |
| 2607 (void)bltstack.pop(); // Remove post-visited node from stack | |
| 2608 } | |
| 2609 } | |
| 2610 } | |
| 2611 | |
| 2612 //------------------------------build_loop_tree_impl--------------------------- | |
| 2613 int PhaseIdealLoop::build_loop_tree_impl( Node *n, int pre_order ) { | |
| 2614 // ---- Post-pass Work ---- | |
| 2615 // Pre-walked but not post-walked nodes need a pre_order number. | |
| 2616 | |
| 2617 // Tightest enclosing loop for this Node | |
| 2618 IdealLoopTree *innermost = NULL; | |
| 2619 | |
| 2620 // For all children, see if any edge is a backedge. If so, make a loop | |
| 2621 // for it. Then find the tightest enclosing loop for the self Node. | |
| 2622 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) { | |
| 2623 Node* m = n->fast_out(i); // Child | |
| 2624 if( n == m ) continue; // Ignore control self-cycles | |
| 2625 if( !m->is_CFG() ) continue;// Ignore non-CFG edges | |
| 2626 | |
| 2627 IdealLoopTree *l; // Child's loop | |
| 2628 if( !is_postvisited(m) ) { // Child visited but not post-visited? | |
| 2629 // Found a backedge | |
| 2630 assert( get_preorder(m) < pre_order, "should be backedge" ); | |
| 2631 // Check for the RootNode, which is already a LoopNode and is allowed | |
| 2632 // to have multiple "backedges". | |
| 2633 if( m == C->root()) { // Found the root? | |
| 2634 l = _ltree_root; // Root is the outermost LoopNode | |
| 2635 } else { // Else found a nested loop | |
| 2636 // Insert a LoopNode to mark this loop. | |
| 2637 l = new IdealLoopTree(this, m, n); | |
| 2638 } // End of Else found a nested loop | |
| 2639 if( !has_loop(m) ) // If 'm' does not already have a loop set | |
| 2640 set_loop(m, l); // Set loop header to loop now | |
| 2641 | |
| 2642 } else { // Else not a nested loop | |
| 2643 if( !_nodes[m->_idx] ) continue; // Dead code has no loop | |
| 2644 l = get_loop(m); // Get previously determined loop | |
| 2645 // If successor is header of a loop (nest), move up-loop till it | |
| 2646 // is a member of some outer enclosing loop. Since there are no | |
| 2647 // shared headers (I've split them already) I only need to go up | |
| 2648 // at most 1 level. | |
| 2649 while( l && l->_head == m ) // Successor heads loop? | |
| 2650 l = l->_parent; // Move up 1 for me | |
| 2651 // If this loop is not properly parented, then this loop | |
| 2652 // has no exit path out, i.e. its an infinite loop. | |
| 2653 if( !l ) { | |
| 2654 // Make loop "reachable" from root so the CFG is reachable. Basically | |
| 2655 // insert a bogus loop exit that is never taken. 'm', the loop head, | |
| 2656 // points to 'n', one (of possibly many) fall-in paths. There may be | |
| 2657 // many backedges as well. | |
| 2658 | |
| 2659 // Here I set the loop to be the root loop. I could have, after | |
| 2660 // inserting a bogus loop exit, restarted the recursion and found my | |
| 2661 // new loop exit. This would make the infinite loop a first-class | |
| 2662 // loop and it would then get properly optimized. What's the use of | |
| 2663 // optimizing an infinite loop? | |
| 2664 l = _ltree_root; // Oops, found infinite loop | |
| 2665 | |
|
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2666 if (!_verify_only) { |
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2667 // Insert the NeverBranch between 'm' and it's control user. |
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2668 NeverBranchNode *iff = new (C, 1) NeverBranchNode( m ); |
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2669 _igvn.register_new_node_with_optimizer(iff); |
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2670 set_loop(iff, l); |
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2671 Node *if_t = new (C, 1) CProjNode( iff, 0 ); |
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2672 _igvn.register_new_node_with_optimizer(if_t); |
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2673 set_loop(if_t, l); |
| 0 | 2674 |
|
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2675 Node* cfg = NULL; // Find the One True Control User of m |
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2676 for (DUIterator_Fast jmax, j = m->fast_outs(jmax); j < jmax; j++) { |
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2677 Node* x = m->fast_out(j); |
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2678 if (x->is_CFG() && x != m && x != iff) |
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2679 { cfg = x; break; } |
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|
2680 } |
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2681 assert(cfg != NULL, "must find the control user of m"); |
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2682 uint k = 0; // Probably cfg->in(0) |
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2683 while( cfg->in(k) != m ) k++; // But check incase cfg is a Region |
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2684 cfg->set_req( k, if_t ); // Now point to NeverBranch |
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2685 |
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2686 // Now create the never-taken loop exit |
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2687 Node *if_f = new (C, 1) CProjNode( iff, 1 ); |
|
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2688 _igvn.register_new_node_with_optimizer(if_f); |
|
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2689 set_loop(if_f, l); |
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2690 // Find frame ptr for Halt. Relies on the optimizer |
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2691 // V-N'ing. Easier and quicker than searching through |
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2692 // the program structure. |
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2693 Node *frame = new (C, 1) ParmNode( C->start(), TypeFunc::FramePtr ); |
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2694 _igvn.register_new_node_with_optimizer(frame); |
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2695 // Halt & Catch Fire |
|
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2696 Node *halt = new (C, TypeFunc::Parms) HaltNode( if_f, frame ); |
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2697 _igvn.register_new_node_with_optimizer(halt); |
|
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2698 set_loop(halt, l); |
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2699 C->root()->add_req(halt); |
| 0 | 2700 } |
| 2701 set_loop(C->root(), _ltree_root); | |
| 2702 } | |
| 2703 } | |
| 2704 // Weeny check for irreducible. This child was already visited (this | |
| 2705 // IS the post-work phase). Is this child's loop header post-visited | |
| 2706 // as well? If so, then I found another entry into the loop. | |
|
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2707 if (!_verify_only) { |
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2708 while( is_postvisited(l->_head) ) { |
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2709 // found irreducible |
|
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2710 l->_irreducible = 1; // = true |
|
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2711 l = l->_parent; |
|
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2712 _has_irreducible_loops = true; |
|
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2713 // Check for bad CFG here to prevent crash, and bailout of compile |
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2714 if (l == NULL) { |
|
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2715 C->record_method_not_compilable("unhandled CFG detected during loop optimization"); |
|
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2716 return pre_order; |
|
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|
2717 } |
| 0 | 2718 } |
| 2719 } | |
| 2720 | |
| 2721 // This Node might be a decision point for loops. It is only if | |
| 2722 // it's children belong to several different loops. The sort call | |
| 2723 // does a trivial amount of work if there is only 1 child or all | |
| 2724 // children belong to the same loop. If however, the children | |
| 2725 // belong to different loops, the sort call will properly set the | |
| 2726 // _parent pointers to show how the loops nest. | |
| 2727 // | |
| 2728 // In any case, it returns the tightest enclosing loop. | |
| 2729 innermost = sort( l, innermost ); | |
| 2730 } | |
| 2731 | |
| 2732 // Def-use info will have some dead stuff; dead stuff will have no | |
| 2733 // loop decided on. | |
| 2734 | |
| 2735 // Am I a loop header? If so fix up my parent's child and next ptrs. | |
| 2736 if( innermost && innermost->_head == n ) { | |
| 2737 assert( get_loop(n) == innermost, "" ); | |
| 2738 IdealLoopTree *p = innermost->_parent; | |
| 2739 IdealLoopTree *l = innermost; | |
| 2740 while( p && l->_head == n ) { | |
| 2741 l->_next = p->_child; // Put self on parents 'next child' | |
| 2742 p->_child = l; // Make self as first child of parent | |
| 2743 l = p; // Now walk up the parent chain | |
| 2744 p = l->_parent; | |
| 2745 } | |
| 2746 } else { | |
| 2747 // Note that it is possible for a LoopNode to reach here, if the | |
| 2748 // backedge has been made unreachable (hence the LoopNode no longer | |
| 2749 // denotes a Loop, and will eventually be removed). | |
| 2750 | |
| 2751 // Record tightest enclosing loop for self. Mark as post-visited. | |
| 2752 set_loop(n, innermost); | |
| 2753 // Also record has_call flag early on | |
| 2754 if( innermost ) { | |
| 2755 if( n->is_Call() && !n->is_CallLeaf() && !n->is_macro() ) { | |
| 2756 // Do not count uncommon calls | |
| 2757 if( !n->is_CallStaticJava() || !n->as_CallStaticJava()->_name ) { | |
| 2758 Node *iff = n->in(0)->in(0); | |
| 2759 if( !iff->is_If() || | |
| 2760 (n->in(0)->Opcode() == Op_IfFalse && | |
| 2761 (1.0 - iff->as_If()->_prob) >= 0.01) || | |
| 2762 (iff->as_If()->_prob >= 0.01) ) | |
| 2763 innermost->_has_call = 1; | |
| 2764 } | |
|
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2765 } else if( n->is_Allocate() && n->as_Allocate()->_is_scalar_replaceable ) { |
|
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2766 // Disable loop optimizations if the loop has a scalar replaceable |
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2767 // allocation. This disabling may cause a potential performance lost |
|
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2768 // if the allocation is not eliminated for some reason. |
|
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2769 innermost->_allow_optimizations = false; |
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|
2770 innermost->_has_call = 1; // = true |
| 0 | 2771 } |
| 2772 } | |
| 2773 } | |
| 2774 | |
| 2775 // Flag as post-visited now | |
| 2776 set_postvisited(n); | |
| 2777 return pre_order; | |
| 2778 } | |
| 2779 | |
| 2780 | |
| 2781 //------------------------------build_loop_early------------------------------- | |
| 2782 // Put Data nodes into some loop nest, by setting the _nodes[]->loop mapping. | |
| 2783 // First pass computes the earliest controlling node possible. This is the | |
| 2784 // controlling input with the deepest dominating depth. | |
|
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2785 void PhaseIdealLoop::build_loop_early( VectorSet &visited, Node_List &worklist, Node_Stack &nstack ) { |
| 0 | 2786 while (worklist.size() != 0) { |
| 2787 // Use local variables nstack_top_n & nstack_top_i to cache values | |
| 2788 // on nstack's top. | |
| 2789 Node *nstack_top_n = worklist.pop(); | |
| 2790 uint nstack_top_i = 0; | |
| 2791 //while_nstack_nonempty: | |
| 2792 while (true) { | |
| 2793 // Get parent node and next input's index from stack's top. | |
| 2794 Node *n = nstack_top_n; | |
| 2795 uint i = nstack_top_i; | |
| 2796 uint cnt = n->req(); // Count of inputs | |
| 2797 if (i == 0) { // Pre-process the node. | |
| 2798 if( has_node(n) && // Have either loop or control already? | |
| 2799 !has_ctrl(n) ) { // Have loop picked out already? | |
| 2800 // During "merge_many_backedges" we fold up several nested loops | |
| 2801 // into a single loop. This makes the members of the original | |
| 2802 // loop bodies pointing to dead loops; they need to move up | |
| 2803 // to the new UNION'd larger loop. I set the _head field of these | |
| 2804 // dead loops to NULL and the _parent field points to the owning | |
| 2805 // loop. Shades of UNION-FIND algorithm. | |
| 2806 IdealLoopTree *ilt; | |
| 2807 while( !(ilt = get_loop(n))->_head ) { | |
| 2808 // Normally I would use a set_loop here. But in this one special | |
| 2809 // case, it is legal (and expected) to change what loop a Node | |
| 2810 // belongs to. | |
| 2811 _nodes.map(n->_idx, (Node*)(ilt->_parent) ); | |
| 2812 } | |
| 2813 // Remove safepoints ONLY if I've already seen I don't need one. | |
| 2814 // (the old code here would yank a 2nd safepoint after seeing a | |
| 2815 // first one, even though the 1st did not dominate in the loop body | |
| 2816 // and thus could be avoided indefinitely) | |
|
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|
2817 if( !_verify_only && !_verify_me && ilt->_has_sfpt && n->Opcode() == Op_SafePoint && |
| 0 | 2818 is_deleteable_safept(n)) { |
| 2819 Node *in = n->in(TypeFunc::Control); | |
| 2820 lazy_replace(n,in); // Pull safepoint now | |
| 2821 // Carry on with the recursion "as if" we are walking | |
| 2822 // only the control input | |
| 2823 if( !visited.test_set( in->_idx ) ) { | |
| 2824 worklist.push(in); // Visit this guy later, using worklist | |
| 2825 } | |
| 2826 // Get next node from nstack: | |
| 2827 // - skip n's inputs processing by setting i > cnt; | |
| 2828 // - we also will not call set_early_ctrl(n) since | |
| 2829 // has_node(n) == true (see the condition above). | |
| 2830 i = cnt + 1; | |
| 2831 } | |
| 2832 } | |
| 2833 } // if (i == 0) | |
| 2834 | |
| 2835 // Visit all inputs | |
| 2836 bool done = true; // Assume all n's inputs will be processed | |
| 2837 while (i < cnt) { | |
| 2838 Node *in = n->in(i); | |
| 2839 ++i; | |
| 2840 if (in == NULL) continue; | |
| 2841 if (in->pinned() && !in->is_CFG()) | |
| 2842 set_ctrl(in, in->in(0)); | |
| 2843 int is_visited = visited.test_set( in->_idx ); | |
| 2844 if (!has_node(in)) { // No controlling input yet? | |
| 2845 assert( !in->is_CFG(), "CFG Node with no controlling input?" ); | |
| 2846 assert( !is_visited, "visit only once" ); | |
| 2847 nstack.push(n, i); // Save parent node and next input's index. | |
| 2848 nstack_top_n = in; // Process current input now. | |
| 2849 nstack_top_i = 0; | |
| 2850 done = false; // Not all n's inputs processed. | |
| 2851 break; // continue while_nstack_nonempty; | |
| 2852 } else if (!is_visited) { | |
| 2853 // This guy has a location picked out for him, but has not yet | |
| 2854 // been visited. Happens to all CFG nodes, for instance. | |
| 2855 // Visit him using the worklist instead of recursion, to break | |
| 2856 // cycles. Since he has a location already we do not need to | |
| 2857 // find his location before proceeding with the current Node. | |
| 2858 worklist.push(in); // Visit this guy later, using worklist | |
| 2859 } | |
| 2860 } | |
| 2861 if (done) { | |
| 2862 // All of n's inputs have been processed, complete post-processing. | |
| 2863 | |
| 605 | 2864 // Compute earliest point this Node can go. |
| 0 | 2865 // CFG, Phi, pinned nodes already know their controlling input. |
| 2866 if (!has_node(n)) { | |
| 2867 // Record earliest legal location | |
| 2868 set_early_ctrl( n ); | |
| 2869 } | |
| 2870 if (nstack.is_empty()) { | |
| 2871 // Finished all nodes on stack. | |
| 2872 // Process next node on the worklist. | |
| 2873 break; | |
| 2874 } | |
| 2875 // Get saved parent node and next input's index. | |
| 2876 nstack_top_n = nstack.node(); | |
| 2877 nstack_top_i = nstack.index(); | |
| 2878 nstack.pop(); | |
| 2879 } | |
| 2880 } // while (true) | |
| 2881 } | |
| 2882 } | |
| 2883 | |
| 2884 //------------------------------dom_lca_internal-------------------------------- | |
| 2885 // Pair-wise LCA | |
| 2886 Node *PhaseIdealLoop::dom_lca_internal( Node *n1, Node *n2 ) const { | |
| 2887 if( !n1 ) return n2; // Handle NULL original LCA | |
| 2888 assert( n1->is_CFG(), "" ); | |
| 2889 assert( n2->is_CFG(), "" ); | |
| 2890 // find LCA of all uses | |
| 2891 uint d1 = dom_depth(n1); | |
| 2892 uint d2 = dom_depth(n2); | |
| 2893 while (n1 != n2) { | |
| 2894 if (d1 > d2) { | |
| 2895 n1 = idom(n1); | |
| 2896 d1 = dom_depth(n1); | |
| 2897 } else if (d1 < d2) { | |
| 2898 n2 = idom(n2); | |
| 2899 d2 = dom_depth(n2); | |
| 2900 } else { | |
| 2901 // Here d1 == d2. Due to edits of the dominator-tree, sections | |
| 2902 // of the tree might have the same depth. These sections have | |
| 2903 // to be searched more carefully. | |
| 2904 | |
| 2905 // Scan up all the n1's with equal depth, looking for n2. | |
| 2906 Node *t1 = idom(n1); | |
| 2907 while (dom_depth(t1) == d1) { | |
| 2908 if (t1 == n2) return n2; | |
| 2909 t1 = idom(t1); | |
| 2910 } | |
| 2911 // Scan up all the n2's with equal depth, looking for n1. | |
| 2912 Node *t2 = idom(n2); | |
| 2913 while (dom_depth(t2) == d2) { | |
| 2914 if (t2 == n1) return n1; | |
| 2915 t2 = idom(t2); | |
| 2916 } | |
| 2917 // Move up to a new dominator-depth value as well as up the dom-tree. | |
| 2918 n1 = t1; | |
| 2919 n2 = t2; | |
| 2920 d1 = dom_depth(n1); | |
| 2921 d2 = dom_depth(n2); | |
| 2922 } | |
| 2923 } | |
| 2924 return n1; | |
| 2925 } | |
| 2926 | |
| 2927 //------------------------------compute_idom----------------------------------- | |
| 2928 // Locally compute IDOM using dom_lca call. Correct only if the incoming | |
| 2929 // IDOMs are correct. | |
| 2930 Node *PhaseIdealLoop::compute_idom( Node *region ) const { | |
| 2931 assert( region->is_Region(), "" ); | |
| 2932 Node *LCA = NULL; | |
| 2933 for( uint i = 1; i < region->req(); i++ ) { | |
| 2934 if( region->in(i) != C->top() ) | |
| 2935 LCA = dom_lca( LCA, region->in(i) ); | |
| 2936 } | |
| 2937 return LCA; | |
| 2938 } | |
| 2939 | |
|
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|
2940 bool PhaseIdealLoop::verify_dominance(Node* n, Node* use, Node* LCA, Node* early) { |
|
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|
2941 bool had_error = false; |
|
046932b72aa2
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diff
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|
2942 #ifdef ASSERT |
|
046932b72aa2
6862956: PhaseIdealLoop should have a CFG verification mode
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681
diff
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|
2943 if (early != C->root()) { |
|
046932b72aa2
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diff
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|
2944 // Make sure that there's a dominance path from use to LCA |
|
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diff
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|
2945 Node* d = use; |
|
046932b72aa2
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diff
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|
2946 while (d != LCA) { |
|
046932b72aa2
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never
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681
diff
changeset
|
2947 d = idom(d); |
|
046932b72aa2
6862956: PhaseIdealLoop should have a CFG verification mode
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diff
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|
2948 if (d == C->root()) { |
|
046932b72aa2
6862956: PhaseIdealLoop should have a CFG verification mode
never
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diff
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|
2949 tty->print_cr("*** Use %d isn't dominated by def %s", use->_idx, n->_idx); |
|
046932b72aa2
6862956: PhaseIdealLoop should have a CFG verification mode
never
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diff
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|
2950 n->dump(); |
|
046932b72aa2
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diff
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|
2951 use->dump(); |
|
046932b72aa2
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diff
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|
2952 had_error = true; |
|
046932b72aa2
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never
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681
diff
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|
2953 break; |
|
046932b72aa2
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never
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681
diff
changeset
|
2954 } |
|
046932b72aa2
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never
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diff
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|
2955 } |
|
046932b72aa2
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|
2956 } |
|
046932b72aa2
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never
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diff
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|
2957 #endif |
|
046932b72aa2
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never
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681
diff
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|
2958 return had_error; |
|
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diff
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|
2959 } |
| 0 | 2960 |
|
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|
2961 |
|
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|
2962 Node* PhaseIdealLoop::compute_lca_of_uses(Node* n, Node* early, bool verify) { |
| 0 | 2963 // Compute LCA over list of uses |
|
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|
2964 bool had_error = false; |
| 0 | 2965 Node *LCA = NULL; |
| 2966 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax && LCA != early; i++) { | |
| 2967 Node* c = n->fast_out(i); | |
| 2968 if (_nodes[c->_idx] == NULL) | |
| 2969 continue; // Skip the occasional dead node | |
| 2970 if( c->is_Phi() ) { // For Phis, we must land above on the path | |
| 2971 for( uint j=1; j<c->req(); j++ ) {// For all inputs | |
| 2972 if( c->in(j) == n ) { // Found matching input? | |
| 2973 Node *use = c->in(0)->in(j); | |
|
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2974 if (_verify_only && use->is_top()) continue; |
| 0 | 2975 LCA = dom_lca_for_get_late_ctrl( LCA, use, n ); |
|
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2976 if (verify) had_error = verify_dominance(n, use, LCA, early) || had_error; |
| 0 | 2977 } |
| 2978 } | |
| 2979 } else { | |
| 2980 // For CFG data-users, use is in the block just prior | |
| 2981 Node *use = has_ctrl(c) ? get_ctrl(c) : c->in(0); | |
| 2982 LCA = dom_lca_for_get_late_ctrl( LCA, use, n ); | |
|
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2983 if (verify) had_error = verify_dominance(n, use, LCA, early) || had_error; |
| 0 | 2984 } |
| 2985 } | |
|
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2986 assert(!had_error, "bad dominance"); |
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2987 return LCA; |
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2988 } |
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2989 |
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2990 //------------------------------get_late_ctrl---------------------------------- |
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2991 // Compute latest legal control. |
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2992 Node *PhaseIdealLoop::get_late_ctrl( Node *n, Node *early ) { |
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2993 assert(early != NULL, "early control should not be NULL"); |
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2994 |
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2995 Node* LCA = compute_lca_of_uses(n, early); |
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2996 #ifdef ASSERT |
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2997 if (LCA == C->root() && LCA != early) { |
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2998 // def doesn't dominate uses so print some useful debugging output |
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2999 compute_lca_of_uses(n, early, true); |
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3000 } |
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3001 #endif |
| 0 | 3002 |
| 3003 // if this is a load, check for anti-dependent stores | |
| 3004 // We use a conservative algorithm to identify potential interfering | |
| 3005 // instructions and for rescheduling the load. The users of the memory | |
| 3006 // input of this load are examined. Any use which is not a load and is | |
| 3007 // dominated by early is considered a potentially interfering store. | |
| 3008 // This can produce false positives. | |
| 3009 if (n->is_Load() && LCA != early) { | |
| 3010 Node_List worklist; | |
| 3011 | |
| 3012 Node *mem = n->in(MemNode::Memory); | |
| 3013 for (DUIterator_Fast imax, i = mem->fast_outs(imax); i < imax; i++) { | |
| 3014 Node* s = mem->fast_out(i); | |
| 3015 worklist.push(s); | |
| 3016 } | |
| 3017 while(worklist.size() != 0 && LCA != early) { | |
| 3018 Node* s = worklist.pop(); | |
| 3019 if (s->is_Load()) { | |
| 3020 continue; | |
| 3021 } else if (s->is_MergeMem()) { | |
| 3022 for (DUIterator_Fast imax, i = s->fast_outs(imax); i < imax; i++) { | |
| 3023 Node* s1 = s->fast_out(i); | |
| 3024 worklist.push(s1); | |
| 3025 } | |
| 3026 } else { | |
| 3027 Node *sctrl = has_ctrl(s) ? get_ctrl(s) : s->in(0); | |
| 3028 assert(sctrl != NULL || s->outcnt() == 0, "must have control"); | |
| 3029 if (sctrl != NULL && !sctrl->is_top() && is_dominator(early, sctrl)) { | |
| 3030 LCA = dom_lca_for_get_late_ctrl(LCA, sctrl, n); | |
| 3031 } | |
| 3032 } | |
| 3033 } | |
| 3034 } | |
| 3035 | |
| 3036 assert(LCA == find_non_split_ctrl(LCA), "unexpected late control"); | |
| 3037 return LCA; | |
| 3038 } | |
| 3039 | |
| 3040 // true if CFG node d dominates CFG node n | |
| 3041 bool PhaseIdealLoop::is_dominator(Node *d, Node *n) { | |
| 3042 if (d == n) | |
| 3043 return true; | |
| 3044 assert(d->is_CFG() && n->is_CFG(), "must have CFG nodes"); | |
| 3045 uint dd = dom_depth(d); | |
| 3046 while (dom_depth(n) >= dd) { | |
| 3047 if (n == d) | |
| 3048 return true; | |
| 3049 n = idom(n); | |
| 3050 } | |
| 3051 return false; | |
| 3052 } | |
| 3053 | |
| 3054 //------------------------------dom_lca_for_get_late_ctrl_internal------------- | |
| 3055 // Pair-wise LCA with tags. | |
| 3056 // Tag each index with the node 'tag' currently being processed | |
| 3057 // before advancing up the dominator chain using idom(). | |
| 3058 // Later calls that find a match to 'tag' know that this path has already | |
| 3059 // been considered in the current LCA (which is input 'n1' by convention). | |
| 3060 // Since get_late_ctrl() is only called once for each node, the tag array | |
| 3061 // does not need to be cleared between calls to get_late_ctrl(). | |
| 3062 // Algorithm trades a larger constant factor for better asymptotic behavior | |
| 3063 // | |
| 3064 Node *PhaseIdealLoop::dom_lca_for_get_late_ctrl_internal( Node *n1, Node *n2, Node *tag ) { | |
| 3065 uint d1 = dom_depth(n1); | |
| 3066 uint d2 = dom_depth(n2); | |
| 3067 | |
| 3068 do { | |
| 3069 if (d1 > d2) { | |
| 3070 // current lca is deeper than n2 | |
| 3071 _dom_lca_tags.map(n1->_idx, tag); | |
| 3072 n1 = idom(n1); | |
| 3073 d1 = dom_depth(n1); | |
| 3074 } else if (d1 < d2) { | |
| 3075 // n2 is deeper than current lca | |
| 3076 Node *memo = _dom_lca_tags[n2->_idx]; | |
| 3077 if( memo == tag ) { | |
| 3078 return n1; // Return the current LCA | |
| 3079 } | |
| 3080 _dom_lca_tags.map(n2->_idx, tag); | |
| 3081 n2 = idom(n2); | |
| 3082 d2 = dom_depth(n2); | |
| 3083 } else { | |
| 3084 // Here d1 == d2. Due to edits of the dominator-tree, sections | |
| 3085 // of the tree might have the same depth. These sections have | |
| 3086 // to be searched more carefully. | |
| 3087 | |
| 3088 // Scan up all the n1's with equal depth, looking for n2. | |
| 3089 _dom_lca_tags.map(n1->_idx, tag); | |
| 3090 Node *t1 = idom(n1); | |
| 3091 while (dom_depth(t1) == d1) { | |
| 3092 if (t1 == n2) return n2; | |
| 3093 _dom_lca_tags.map(t1->_idx, tag); | |
| 3094 t1 = idom(t1); | |
| 3095 } | |
| 3096 // Scan up all the n2's with equal depth, looking for n1. | |
| 3097 _dom_lca_tags.map(n2->_idx, tag); | |
| 3098 Node *t2 = idom(n2); | |
| 3099 while (dom_depth(t2) == d2) { | |
| 3100 if (t2 == n1) return n1; | |
| 3101 _dom_lca_tags.map(t2->_idx, tag); | |
| 3102 t2 = idom(t2); | |
| 3103 } | |
| 3104 // Move up to a new dominator-depth value as well as up the dom-tree. | |
| 3105 n1 = t1; | |
| 3106 n2 = t2; | |
| 3107 d1 = dom_depth(n1); | |
| 3108 d2 = dom_depth(n2); | |
| 3109 } | |
| 3110 } while (n1 != n2); | |
| 3111 return n1; | |
| 3112 } | |
| 3113 | |
| 3114 //------------------------------init_dom_lca_tags------------------------------ | |
| 3115 // Tag could be a node's integer index, 32bits instead of 64bits in some cases | |
| 3116 // Intended use does not involve any growth for the array, so it could | |
| 3117 // be of fixed size. | |
| 3118 void PhaseIdealLoop::init_dom_lca_tags() { | |
| 3119 uint limit = C->unique() + 1; | |
| 3120 _dom_lca_tags.map( limit, NULL ); | |
| 3121 #ifdef ASSERT | |
| 3122 for( uint i = 0; i < limit; ++i ) { | |
| 3123 assert(_dom_lca_tags[i] == NULL, "Must be distinct from each node pointer"); | |
| 3124 } | |
| 3125 #endif // ASSERT | |
| 3126 } | |
| 3127 | |
| 3128 //------------------------------clear_dom_lca_tags------------------------------ | |
| 3129 // Tag could be a node's integer index, 32bits instead of 64bits in some cases | |
| 3130 // Intended use does not involve any growth for the array, so it could | |
| 3131 // be of fixed size. | |
| 3132 void PhaseIdealLoop::clear_dom_lca_tags() { | |
| 3133 uint limit = C->unique() + 1; | |
| 3134 _dom_lca_tags.map( limit, NULL ); | |
| 3135 _dom_lca_tags.clear(); | |
| 3136 #ifdef ASSERT | |
| 3137 for( uint i = 0; i < limit; ++i ) { | |
| 3138 assert(_dom_lca_tags[i] == NULL, "Must be distinct from each node pointer"); | |
| 3139 } | |
| 3140 #endif // ASSERT | |
| 3141 } | |
| 3142 | |
| 3143 //------------------------------build_loop_late-------------------------------- | |
| 3144 // Put Data nodes into some loop nest, by setting the _nodes[]->loop mapping. | |
| 3145 // Second pass finds latest legal placement, and ideal loop placement. | |
|
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3146 void PhaseIdealLoop::build_loop_late( VectorSet &visited, Node_List &worklist, Node_Stack &nstack ) { |
| 0 | 3147 while (worklist.size() != 0) { |
| 3148 Node *n = worklist.pop(); | |
| 3149 // Only visit once | |
| 3150 if (visited.test_set(n->_idx)) continue; | |
| 3151 uint cnt = n->outcnt(); | |
| 3152 uint i = 0; | |
| 3153 while (true) { | |
| 3154 assert( _nodes[n->_idx], "no dead nodes" ); | |
| 3155 // Visit all children | |
| 3156 if (i < cnt) { | |
| 3157 Node* use = n->raw_out(i); | |
| 3158 ++i; | |
| 3159 // Check for dead uses. Aggressively prune such junk. It might be | |
| 3160 // dead in the global sense, but still have local uses so I cannot | |
| 3161 // easily call 'remove_dead_node'. | |
| 3162 if( _nodes[use->_idx] != NULL || use->is_top() ) { // Not dead? | |
| 3163 // Due to cycles, we might not hit the same fixed point in the verify | |
| 3164 // pass as we do in the regular pass. Instead, visit such phis as | |
| 3165 // simple uses of the loop head. | |
| 3166 if( use->in(0) && (use->is_CFG() || use->is_Phi()) ) { | |
| 3167 if( !visited.test(use->_idx) ) | |
| 3168 worklist.push(use); | |
| 3169 } else if( !visited.test_set(use->_idx) ) { | |
| 3170 nstack.push(n, i); // Save parent and next use's index. | |
| 3171 n = use; // Process all children of current use. | |
| 3172 cnt = use->outcnt(); | |
| 3173 i = 0; | |
| 3174 } | |
| 3175 } else { | |
| 3176 // Do not visit around the backedge of loops via data edges. | |
| 3177 // push dead code onto a worklist | |
| 3178 _deadlist.push(use); | |
| 3179 } | |
| 3180 } else { | |
| 3181 // All of n's children have been processed, complete post-processing. | |
|
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3182 build_loop_late_post(n); |
| 0 | 3183 if (nstack.is_empty()) { |
| 3184 // Finished all nodes on stack. | |
| 3185 // Process next node on the worklist. | |
| 3186 break; | |
| 3187 } | |
| 3188 // Get saved parent node and next use's index. Visit the rest of uses. | |
| 3189 n = nstack.node(); | |
| 3190 cnt = n->outcnt(); | |
| 3191 i = nstack.index(); | |
| 3192 nstack.pop(); | |
| 3193 } | |
| 3194 } | |
| 3195 } | |
| 3196 } | |
| 3197 | |
| 3198 //------------------------------build_loop_late_post--------------------------- | |
| 3199 // Put Data nodes into some loop nest, by setting the _nodes[]->loop mapping. | |
| 3200 // Second pass finds latest legal placement, and ideal loop placement. | |
|
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3201 void PhaseIdealLoop::build_loop_late_post( Node *n ) { |
| 0 | 3202 |
|
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3203 if (n->req() == 2 && n->Opcode() == Op_ConvI2L && !C->major_progress() && !_verify_only) { |
| 0 | 3204 _igvn._worklist.push(n); // Maybe we'll normalize it, if no more loops. |
| 3205 } | |
| 3206 | |
| 3207 // CFG and pinned nodes already handled | |
| 3208 if( n->in(0) ) { | |
| 3209 if( n->in(0)->is_top() ) return; // Dead? | |
| 3210 | |
| 3211 // We'd like +VerifyLoopOptimizations to not believe that Mod's/Loads | |
| 3212 // _must_ be pinned (they have to observe their control edge of course). | |
| 3213 // Unlike Stores (which modify an unallocable resource, the memory | |
| 3214 // state), Mods/Loads can float around. So free them up. | |
| 3215 bool pinned = true; | |
| 3216 switch( n->Opcode() ) { | |
| 3217 case Op_DivI: | |
| 3218 case Op_DivF: | |
| 3219 case Op_DivD: | |
| 3220 case Op_ModI: | |
| 3221 case Op_ModF: | |
| 3222 case Op_ModD: | |
| 3223 case Op_LoadB: // Same with Loads; they can sink | |
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3224 case Op_LoadUS: // during loop optimizations. |
| 0 | 3225 case Op_LoadD: |
| 3226 case Op_LoadF: | |
| 3227 case Op_LoadI: | |
| 3228 case Op_LoadKlass: | |
|
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3229 case Op_LoadNKlass: |
| 0 | 3230 case Op_LoadL: |
| 3231 case Op_LoadS: | |
| 3232 case Op_LoadP: | |
|
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3233 case Op_LoadN: |
| 0 | 3234 case Op_LoadRange: |
| 3235 case Op_LoadD_unaligned: | |
| 3236 case Op_LoadL_unaligned: | |
| 3237 case Op_StrComp: // Does a bunch of load-like effects | |
| 681 | 3238 case Op_StrEquals: |
| 3239 case Op_StrIndexOf: | |
|
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3240 case Op_AryEq: |
| 0 | 3241 pinned = false; |
| 3242 } | |
| 3243 if( pinned ) { | |
| 605 | 3244 IdealLoopTree *chosen_loop = get_loop(n->is_CFG() ? n : get_ctrl(n)); |
| 3245 if( !chosen_loop->_child ) // Inner loop? | |
| 3246 chosen_loop->_body.push(n); // Collect inner loops | |
| 0 | 3247 return; |
| 3248 } | |
| 3249 } else { // No slot zero | |
| 3250 if( n->is_CFG() ) { // CFG with no slot 0 is dead | |
| 3251 _nodes.map(n->_idx,0); // No block setting, it's globally dead | |
| 3252 return; | |
| 3253 } | |
| 3254 assert(!n->is_CFG() || n->outcnt() == 0, ""); | |
| 3255 } | |
| 3256 | |
| 3257 // Do I have a "safe range" I can select over? | |
| 3258 Node *early = get_ctrl(n);// Early location already computed | |
| 3259 | |
| 3260 // Compute latest point this Node can go | |
| 3261 Node *LCA = get_late_ctrl( n, early ); | |
| 3262 // LCA is NULL due to uses being dead | |
| 3263 if( LCA == NULL ) { | |
| 3264 #ifdef ASSERT | |
| 3265 for (DUIterator i1 = n->outs(); n->has_out(i1); i1++) { | |
| 3266 assert( _nodes[n->out(i1)->_idx] == NULL, "all uses must also be dead"); | |
| 3267 } | |
| 3268 #endif | |
| 3269 _nodes.map(n->_idx, 0); // This node is useless | |
| 3270 _deadlist.push(n); | |
| 3271 return; | |
| 3272 } | |
| 3273 assert(LCA != NULL && !LCA->is_top(), "no dead nodes"); | |
| 3274 | |
| 3275 Node *legal = LCA; // Walk 'legal' up the IDOM chain | |
| 3276 Node *least = legal; // Best legal position so far | |
| 3277 while( early != legal ) { // While not at earliest legal | |
| 1172 | 3278 #ifdef ASSERT |
| 3279 if (legal->is_Start() && !early->is_Root()) { | |
| 3280 // Bad graph. Print idom path and fail. | |
| 3281 tty->print_cr( "Bad graph detected in build_loop_late"); | |
| 3282 tty->print("n: ");n->dump(); tty->cr(); | |
| 3283 tty->print("early: ");early->dump(); tty->cr(); | |
| 3284 int ct = 0; | |
| 3285 Node *dbg_legal = LCA; | |
| 3286 while(!dbg_legal->is_Start() && ct < 100) { | |
| 3287 tty->print("idom[%d] ",ct); dbg_legal->dump(); tty->cr(); | |
| 3288 ct++; | |
| 3289 dbg_legal = idom(dbg_legal); | |
| 3290 } | |
| 3291 assert(false, "Bad graph detected in build_loop_late"); | |
| 3292 } | |
| 3293 #endif | |
| 0 | 3294 // Find least loop nesting depth |
| 3295 legal = idom(legal); // Bump up the IDOM tree | |
| 3296 // Check for lower nesting depth | |
| 3297 if( get_loop(legal)->_nest < get_loop(least)->_nest ) | |
| 3298 least = legal; | |
| 3299 } | |
|
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3300 assert(early == legal || legal != C->root(), "bad dominance of inputs"); |
| 0 | 3301 |
| 3302 // Try not to place code on a loop entry projection | |
| 3303 // which can inhibit range check elimination. | |
| 3304 if (least != early) { | |
| 3305 Node* ctrl_out = least->unique_ctrl_out(); | |
| 3306 if (ctrl_out && ctrl_out->is_CountedLoop() && | |
| 3307 least == ctrl_out->in(LoopNode::EntryControl)) { | |
| 3308 Node* least_dom = idom(least); | |
| 3309 if (get_loop(least_dom)->is_member(get_loop(least))) { | |
| 3310 least = least_dom; | |
| 3311 } | |
| 3312 } | |
| 3313 } | |
| 3314 | |
| 3315 #ifdef ASSERT | |
| 3316 // If verifying, verify that 'verify_me' has a legal location | |
| 3317 // and choose it as our location. | |
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3318 if( _verify_me ) { |
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3319 Node *v_ctrl = _verify_me->get_ctrl_no_update(n); |
| 0 | 3320 Node *legal = LCA; |
| 3321 while( early != legal ) { // While not at earliest legal | |
| 3322 if( legal == v_ctrl ) break; // Check for prior good location | |
| 3323 legal = idom(legal) ;// Bump up the IDOM tree | |
| 3324 } | |
| 3325 // Check for prior good location | |
| 3326 if( legal == v_ctrl ) least = legal; // Keep prior if found | |
| 3327 } | |
| 3328 #endif | |
| 3329 | |
| 3330 // Assign discovered "here or above" point | |
| 3331 least = find_non_split_ctrl(least); | |
| 3332 set_ctrl(n, least); | |
| 3333 | |
| 3334 // Collect inner loop bodies | |
| 605 | 3335 IdealLoopTree *chosen_loop = get_loop(least); |
| 3336 if( !chosen_loop->_child ) // Inner loop? | |
| 3337 chosen_loop->_body.push(n);// Collect inner loops | |
| 0 | 3338 } |
| 3339 | |
| 3340 #ifndef PRODUCT | |
| 3341 //------------------------------dump------------------------------------------- | |
| 3342 void PhaseIdealLoop::dump( ) const { | |
| 3343 ResourceMark rm; | |
| 3344 Arena* arena = Thread::current()->resource_area(); | |
| 3345 Node_Stack stack(arena, C->unique() >> 2); | |
| 3346 Node_List rpo_list; | |
| 3347 VectorSet visited(arena); | |
| 3348 visited.set(C->top()->_idx); | |
| 3349 rpo( C->root(), stack, visited, rpo_list ); | |
| 3350 // Dump root loop indexed by last element in PO order | |
| 3351 dump( _ltree_root, rpo_list.size(), rpo_list ); | |
| 3352 } | |
| 3353 | |
| 3354 void PhaseIdealLoop::dump( IdealLoopTree *loop, uint idx, Node_List &rpo_list ) const { | |
|
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3355 loop->dump_head(); |
| 0 | 3356 |
| 3357 // Now scan for CFG nodes in the same loop | |
| 3358 for( uint j=idx; j > 0; j-- ) { | |
| 3359 Node *n = rpo_list[j-1]; | |
| 3360 if( !_nodes[n->_idx] ) // Skip dead nodes | |
| 3361 continue; | |
| 3362 if( get_loop(n) != loop ) { // Wrong loop nest | |
| 3363 if( get_loop(n)->_head == n && // Found nested loop? | |
| 3364 get_loop(n)->_parent == loop ) | |
| 3365 dump(get_loop(n),rpo_list.size(),rpo_list); // Print it nested-ly | |
| 3366 continue; | |
| 3367 } | |
| 3368 | |
| 3369 // Dump controlling node | |
| 3370 for( uint x = 0; x < loop->_nest; x++ ) | |
| 3371 tty->print(" "); | |
| 3372 tty->print("C"); | |
| 3373 if( n == C->root() ) { | |
| 3374 n->dump(); | |
| 3375 } else { | |
| 3376 Node* cached_idom = idom_no_update(n); | |
| 3377 Node *computed_idom = n->in(0); | |
| 3378 if( n->is_Region() ) { | |
| 3379 computed_idom = compute_idom(n); | |
| 3380 // computed_idom() will return n->in(0) when idom(n) is an IfNode (or | |
| 3381 // any MultiBranch ctrl node), so apply a similar transform to | |
| 3382 // the cached idom returned from idom_no_update. | |
| 3383 cached_idom = find_non_split_ctrl(cached_idom); | |
| 3384 } | |
| 3385 tty->print(" ID:%d",computed_idom->_idx); | |
| 3386 n->dump(); | |
| 3387 if( cached_idom != computed_idom ) { | |
| 3388 tty->print_cr("*** BROKEN IDOM! Computed as: %d, cached as: %d", | |
| 3389 computed_idom->_idx, cached_idom->_idx); | |
| 3390 } | |
| 3391 } | |
| 3392 // Dump nodes it controls | |
| 3393 for( uint k = 0; k < _nodes.Size(); k++ ) { | |
| 3394 // (k < C->unique() && get_ctrl(find(k)) == n) | |
| 3395 if (k < C->unique() && _nodes[k] == (Node*)((intptr_t)n + 1)) { | |
| 3396 Node *m = C->root()->find(k); | |
| 3397 if( m && m->outcnt() > 0 ) { | |
| 3398 if (!(has_ctrl(m) && get_ctrl_no_update(m) == n)) { | |
| 3399 tty->print_cr("*** BROKEN CTRL ACCESSOR! _nodes[k] is %p, ctrl is %p", | |
| 3400 _nodes[k], has_ctrl(m) ? get_ctrl_no_update(m) : NULL); | |
| 3401 } | |
| 3402 for( uint j = 0; j < loop->_nest; j++ ) | |
| 3403 tty->print(" "); | |
| 3404 tty->print(" "); | |
| 3405 m->dump(); | |
| 3406 } | |
| 3407 } | |
| 3408 } | |
| 3409 } | |
| 3410 } | |
| 3411 | |
| 3412 // Collect a R-P-O for the whole CFG. | |
| 3413 // Result list is in post-order (scan backwards for RPO) | |
| 3414 void PhaseIdealLoop::rpo( Node *start, Node_Stack &stk, VectorSet &visited, Node_List &rpo_list ) const { | |
| 3415 stk.push(start, 0); | |
| 3416 visited.set(start->_idx); | |
| 3417 | |
| 3418 while (stk.is_nonempty()) { | |
| 3419 Node* m = stk.node(); | |
| 3420 uint idx = stk.index(); | |
| 3421 if (idx < m->outcnt()) { | |
| 3422 stk.set_index(idx + 1); | |
| 3423 Node* n = m->raw_out(idx); | |
| 3424 if (n->is_CFG() && !visited.test_set(n->_idx)) { | |
| 3425 stk.push(n, 0); | |
| 3426 } | |
| 3427 } else { | |
| 3428 rpo_list.push(m); | |
| 3429 stk.pop(); | |
| 3430 } | |
| 3431 } | |
| 3432 } | |
| 3433 #endif | |
| 3434 | |
| 3435 | |
| 3436 //============================================================================= | |
| 3437 //------------------------------LoopTreeIterator----------------------------------- | |
| 3438 | |
| 3439 // Advance to next loop tree using a preorder, left-to-right traversal. | |
| 3440 void LoopTreeIterator::next() { | |
| 3441 assert(!done(), "must not be done."); | |
| 3442 if (_curnt->_child != NULL) { | |
| 3443 _curnt = _curnt->_child; | |
| 3444 } else if (_curnt->_next != NULL) { | |
| 3445 _curnt = _curnt->_next; | |
| 3446 } else { | |
| 3447 while (_curnt != _root && _curnt->_next == NULL) { | |
| 3448 _curnt = _curnt->_parent; | |
| 3449 } | |
| 3450 if (_curnt == _root) { | |
| 3451 _curnt = NULL; | |
| 3452 assert(done(), "must be done."); | |
| 3453 } else { | |
| 3454 assert(_curnt->_next != NULL, "must be more to do"); | |
| 3455 _curnt = _curnt->_next; | |
| 3456 } | |
| 3457 } | |
| 3458 } |